W1 – Lesson 3: Fractions
Transcript of W1 – Lesson 3: Fractions
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
W1 – Lesson 3: Fractions
Warm-up:
• Icanusepatternblockstomodelfractions.
Fraction Tiles
How many?
1. are in ? _______ 2. are in ? _______
3. are in ? _______ 4. are in ? _______
5. are in ? _______
Based on the relationships above,
1. If = 1. = _______
2. If = 1. = _______
3. If = 1. = _______
4. If = 1. = _______
2
3
2
6
3
1/6
1/3
1/2
2/3
Preview/Review Concepts W1 - Lesson 3MathematicsGrade7
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Now, try some really fun shapes.
1. If + = 1, what is ? _______
2. If + = 1, what is + ? _______
3. If + = 1, what is + ? _______
4. If + = 1, what is ? _______
5. If - = 1, what is + ? _______
1/9
2/8 = 1/4
4
3/7
1
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
Review:
• Iunderstandfractionbasics.
Practice
Example 1: What fraction of the pie has been removed?
One of eight pieces has been removed; therefore, 18
has beenremoved.
Example 2: What fraction of the eggs is left in the carton?
Ten of twelve eggs are still in the carton; therefore 1012
or 56
is left in the carton.
3 numerator or dividend vinculum
7 denominator or divisor
properfraction: a fraction in which the numerator is lessthan the denominator
Example: 23
mixednumber: the sum of a whole number and a proper fraction
Example: 647
improperfraction: a fraction in which the numerator is greaterthan the denominator
Example: 72
vinculum: the line between the numerator and the denominator, showing that the two numbers are connected
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Equivalent Fractions
Example: Write three equivalent fractions for 23
.
46
, 69
, and 812
are all equivalent fractions of 23
.
Multiplying or dividing the numerator and denominator by the same number can generate an unlimited number of equivalent fractions.
Practice
Fill in the blanks to complete the equivalent fractions.
a. 23 15= b.
17 21=
c. 4 18= d. 5 10
12=
e. 7
11 33= f.
618 9
=
g. 8
20 5= h.
33 199
=
i. 2 4
10= j. 3 21
28=
Fractions that represent the same amount are called equivalent fractions.
2 4 2 6 2 83 6 3 9 3 12
X 2
X 2
X 3
X 3
X 4
X 4
10
21
3
3
2 24
23
5 4
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
Reducing Fractions to Simplest Form
Example: Write the fractions in lowest terms.
a. 9 and 12 are both divisible by 3.
The simplest form of 912
is 34
.
b. 712
Because 7 and 12 do not have any numbers by which they are both divisible, the fraction is already in its simplest form.
Practice
Express each fraction in lowest terms.
a. 2 4= b. 4
12=
c. 6 9= d. 5
15=
e. 7 21
= f. 10 18
=
g. 8 24
= h. 50 100
=
i. 312
= j. 5 25
=
A fraction in simplest form is the fraction that cannot be divided to �nd an equivalent fraction.
9 312 4
3÷
3÷
A fraction in simplestform is also known as a reducedfraction or a fraction expressed in lowestterms.
Answers should always be given in lowestterms.
12
13
23
13
13
59
13
12
15
14
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
Objective:
• Icanaddandsubtractfractionswiththesamedenominators..
Practice
Solve. Express your answers in lowest terms..
a. + =1 13 3
b. + =1 57 7
c. + =2 49 9
d. 5 3
10 10+ =
e. 1 36 6+ = f. 11 5
20 20+ = g. 3 2
8 8+ = h. 10 8
12 12− =
i. 17 821 21
− = j. 13 315 15
− = k. 9 510 10
− = l. 7 29 9− =
Subtracting fractions with the same denominator.
Keep the denominator the same; subtract the numerators.
Example: 7 312 12
−
7 3 47 3 4 Therefore, 12 12 12
− −
Adding fractions with the same denominator
Keep the denominator the same; add the numerators.
Example: 1 24 4
1 2 31 2 3 Therefore, 4 4 4
23
67
6 29 3=
8 410 5
=
4 26 3=
16 420 5
=58
2 112 6
=
9 321 7
=10 215 3
= 4 210 5
=59
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Objective:
• Icanaddandsubtractfractionswiththedifferentdenominators..
Practice
Solve. Express your answers in lowest terms..
a. 2 13 7+ = b.
1 36 4+ =
c. 1 42 9+ = d.
6 310 8
+ =
e. 5 5
20 8+ = f.
3 221 3
+ =
g. 10 112 4
− = h. 17 521 7
− =
i. 9 3
10 20− = j.
7 19 3− =
2 810 40
7 358 40
Example 1:
You need a common denominator. 8 and 10 are both factors of 40.
Change:
Change: Subtract:
7 28 10−
35 8 2740 40 40
−
1 34 12
Example 2:
Common denominator: 12
Change:
Add:
OrCommon denominator: 4
Change:
Add:
1 34 12
3 3 6 112 12 12 2
1 1 2 14 4 4 2
3 112 4
14 3 1721 21 21
+ = 2 9 1112 12 12
+ =
9 8 1718 18 18
+ =
10 25 35 740 40 40 8
+ = =3 14 1721 21 21
+ =
10 3 712 12 12
− =17 15 221 21 21
− =
18 3 15 320 20 20 4
− = =7 3 49 9 9− =
24 15 39+ =40 40 40
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Objective:
• Icanmodeltheadditionandsubtractionoffractions.
Grid Model
Note: Use the columns and rows of a grid to represent different denominators.
Example 1: 1 13 4+ =
Example 2: 3 15 3− =
Practice
Draw the grid that represents best the solution. For this activity you do not need to simplify the fraction.
a. + =1 13 3
b. + =1 57 7
c. + =2 49 9
Total squares = 12Number of shaded squares = 7
Answer = 7
12
Total squares = 14Number of shaded squares left = 4
Answer = 4
15
1 of 3 rows = 14
colour in 4 squares 1 of 4 columns = 13
colour in 3 squares
3 of 5 rows = 35
colour in 9 squares1 of 3 columns = 1
3erase 5 squares
2435
1318
2024
2 2=4 6
2 2 =7 5
1 2=2 6
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
d. 1 24 3+ = e. 1 3
5 4+ = f. 1 3
3 10+ =
g. 3 14 3− = h. 4 2
5 3− = i. 6 2
7 6− =
j. 8 49 6− = k. 7 1
8 2− = l. 2 1
3 4− =
1920
1930
215
2242
512
512
1112
1254
616
1 24 3
1 35 4
133
10
1 4 5 3 12 12
2 10 2 3 15 15
2 14 22 6 42 42
4 36 12 6 54 54
1 8 6 2 16 16 1 3 5
4 12 15
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Summary and Practice:
• Usingwhatyoulearnedanswerthefollowingquestions.
1. On the chart below, summarize the steps needed to add or subtract fractions withthe same denominator and fractions with different denominators.
Same Denominators Different Denominators
Steps to add fractions
Steps to subtract fractions
2. Express the fractions in lowest terms.
a. 618
b. 954
c. 1648
d. 1421
3. Using the grid below, write an addition equation represented by the grid.
Answersmayvary
Example:
1. Keepthedenominatorthesame.
2. Addthenumerators,thenreduceifpossible.
Answersmayvary
Example:
1. Findacommondenominator.
2. Changethefractionstoanequivalentfractionwiththenewdenominator.
3. Addthenewnumerators,thenreduceifpossible
Answersmayvary
Example:
1. Keepthedenominatorthesame.
2. subtractthenumerators,thenreduceifpossible.
Answersmayvary
Example:
1. Findacommondenominator.
2. Changethefractionstoanequivalentfractionwiththenewdenominator.
3. Subtractthenewnumerators,thenreduceifpossible
29
=16
=13
=27
=
3 1 145 3 15+ =
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Preview/Review Concepts W1 - Lesson 3 MathematicsGrade7
4. Model using a grid.
a. 3 16 3+ b. 9 3
10 4−
5. 13
of entries in a pet show are cats. 12
of the entries are dogs.
What fraction of the animals is not a cat or a dog?
6. George spent 28
of his spare time playing video games, 26
practising basketball, 14
practising guitar, and the remainder watching TV. What fraction represents the
time he spent watching TV?
6 340 20
= =
1 1 2 3 53 2 6 6 66 5 16 6 61 of the animals is not a cat or a dog.6
+ = + =
− =
2 2 1 6 8 6 20 58 6 4 24 24 24 24 66 5 16 6 6
1George spent of his time watching TV.6
+ + = + + = =
− =
1518
=
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
W1 – Lesson 4: Fractions, Decimals, and Percents
Objective:
• Icanchangeanimproperfractiontoamixednumberandback.
Mixed number: sum of a whole number and a proper fraction.
Example: 647
Writing as a mixed number:
Number of whole pizzas: 2
Fraction of remaining pizza: 34
The mixed number is written as: 324
Improper fraction: when the numerator is greater than the denominator.
Example: 72
Writing as a improper fraction:
Total remaining slices: 11
Number of slices per pizza: 4
The improper fraction then is: 114
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Converting mixed numbers to improper fractions:
Practice
Express the mixed number as an improper fraction.
a.223= b.
335=
c. 217= d. 16
2=
e.429= f.
136=
Converting improper fractions to mixed numbers:
Practice
Express the improper fraction as a mixed number.
a. 112= b.
125
=
c. 237
= d. 143
=
e. 149
= f. 156
=
Example:
1. Multiply the whole number by the denominator. (3 × 4)
2. Add step 1 to thenumerator (12 + 1)
3. Write step 3 as afraction over theoriginaldenominator
134
134
Example:
1. Divide the numerator by the denominator (13 ÷ 3)
2. Write step 1 asthe whole numberand the remainderas a fraction over the original denominator (4 )1
3
133
83
185
97
132
229
196
152
225
237
243
519
3 12 26 2=
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Objective:
• Icanaddandsubtractmixednumbers.
Practice:
Solve. Express your answer in lowest terms.
a. 1 532 7+ = b.
4 11 56 4+ = c.
2 15 26 2+ =
d. 1 36 22 7− = e. 3 13
4 3− = f. 4 22 1
5 3− =
Example 1:
1. Find a common denominator for the fractions.2. Subtract the whole numbers.3. Subtract fractions as usual.
7 and 2 are both factors of 14.
Change:
Change:
Subtract: 12 7 54 2 214 14 14
−
6 14 27 2−
6 12 7 14
1 72 14
Example 2:
Common denominator: 18
Change:
Change:
Add:
4 119 2
4 89 181 92 18
8 9 171 118 18 18
7 10 17 33 3 414 14 14 14
+ = =8 3 111 5 6
12 12 12+ =
2 3 55 2 76 6 6+ =
7 6 16 2 414 14 14
− =9 4 53 3
12 12 12− =
12 10 22 1 115 15 15
− =
Preview/Review Concepts W1 - Lesson 4MathematicsGrade7
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Objective:
• Icanconvertbetweenfractionsanddecimalnumbers.
Converting fractions and terminating decimals:
The shaded area of this grid, as a fraction, is: 36100
The shaded area, written as a decimal, is: 0.36
But consider a fraction like 25
: What would it look like on a grid?
Use your calculator to calculate 2 ÷ 5. What do you notice?
Repeating decimal: a decimal number in which a block of one or more digits repeats in a pattern.
Terminating decimal: a number that is complete after a certain number of digits with no repeats.
Fractions with
denominators of 10,
100, or 1000 are easy
to convert into
decimals by using
place values.
Examples:
210 = 0.2 (tenths place)
7100
= 0.07 (hundredths)
41000
= 0.004 (thousandths)
1. Write 2/5 as a fraction with a denominator of 100:100
2. Shade in the same number of squares as thenumerator.
3. Use the place value to determine the decimal: ______
40
0.4
Theanswersarethesame.
Turn any fraction into a decimal by dividing the numerator by the denominator.
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Example:
25 10.25100 430.3
10
= =
=
Practice
Convert the fractions to decimals, and the decimals to fractions.
a. 15= b. 6
8= c. 3
20=
d. 625
= e. 1440
= f. 924
=
g. 0.7 = h. 0.22 = i. 0.12 =
j. 0.4 = k. 0.33 = l. 0.54 =
Converting fractions and repeating decimals:
Example 1:
5 0.555 555 555 555... 0.592 0.2857142857142857... 0.2857147
= ⇒
= ⇒
Bar notation: a method of writing a repeating decimal using a bar above the digits to represent a repeat.
Turn any fraction into a decimal by dividing the numerator by the denominator.
Convert a terminating decimal to a fraction by using the place value as the denominator and reduce if necessary.
0.2 0.75 0.15
0.24 0.35 0.375
22 11100 50
=
33100
54 27100 50
=
12 3100 25
=7
10
=4 2
10 5
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Example 2:
1 2 3 40.1, 0.2, 0.3, 0.49 9 9 9Predict5 6 7_____, _____, _____9 9 9
= = = =
= = =
Example 3: 0 .27
Think: We know 0.3 is 310
, so the fraction must be a smaller fraction (smaller numerator
or larger denominator) so it may be 210
or3
11. Because 2
10 is non repeating it
must be 311
Check: 3 ÷ 11 = 0.27272727…
Practice
Convert the fractions to decimals, and the decimals to fractions.
a. 17= b. 2
9= c. 5
11=
d. 6
33= e.
299
= f. 724
=
g. 0.7 = h. 0.72 = i. 0.003 =
j. 0.63 = k. 0.28514 = l. 0.16 =
Convert a repeating decimal to a fraction by looking for repeat patterns.
0.5 0.6 0.7
0.142857 0.2 0.45
0.45
79
711
0.02 0.2916
811
31000
16
27
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Objective:
• Icanexpressapercentasadecimalnumber.
Per cent: means “out of 100”
Practice
Write the percent as a decimal.
a. 38% =
b. 29% =
c. 2% =
d. 67% =
e. 8% =
Examples:
78% = 78 ÷ 100 = 0.78
24% = 24 ÷ 100 = 0.24
Convert a percent into a decimal number by dividing by 100.
Examples:
0.777 = 0.777 × 100 = 78%
0.542 = 0.542 × 100 = 54%
Convert a decimal to a percent by multiplying by 100. Remember to round the answer if necessary.
Practice
Write the decimal as a percent.
a. 0.281 =
b. 0.458 =
c. 0.894 =
d. 0.676 =
e. 0.073 =
0.38
0.29
0.02
0.67
0.08
28%
46%
89%
68%
7%
Preview/Review Concepts W1 - Lesson 4MathematicsGrade7
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Objective:
• Icanexpressapercentasafraction
Practice
Write the percent as a fraction.
a. 88% =
b. 27% =
c. 12% =
d. 6% =
e. 48% =
Practice
Write the fraction as a percent.
a. 2562
=
b. 3453
=
c. 1920
=
d. =785
e. 57=
Convert a percent into a fraction by putting the percent as the numerator over a denominator of 100. Simplify.
75% = 75
100= 3
4
35% = 35100
= 720
Example:
Convert a fraction to a percent by �rst converting the fraction to a decimal and multiply by 100. Remember to round the answer.
Example: 2836
28 ÷ 36 = 0.777 × 100 = 78%
88 22100 25
=
2710012 3
100 25=
=6 3
100 5048 12
100 25=
40%
64%
95%
71%
8%
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Converting mixed numbers to improper fractions:
1. How many squares are shaded: _____
a. Write as a fraction: _____
b. Write as a decimal: _____
c. Write as a percent: _____
2. How many squares are white: _____
a. Write as a fraction: _____
b. Write as a decimal: _____
c. Write as a percent: _____
3. Add the percent of shaded to the percent of white. What do you notice?
59%
0.59
59
41%
0.41
41
Thatittotals100%.
59100
41100
Preview/Review Concepts W1 - Lesson 4MathematicsGrade7
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Objective:
• Icanusepercentstosolveproblems.
Practice
a. 25% of 44 =
b. 3% of 70 =
c. 29% of 11 =
d. 48% of 63 =
e. 21% of 89 =
Calculating a number from a percent:
Create two proportional fractions to find the missing number.
Example:
25% of ____ = 10 25% = 25 1 1 10100 4 4 ?
= = the only answer that will fit
in the blank and remain
proportional is 40!
Practice
Convert the fractions to decimals, and the decimals to fractions.
a. 12% of _____ = 54 b. 20% of _____ = 45
c. 30% of _____ = 27 d. 4% of _____ = 24
Proportion: two equivalent ratios or
fractions ( 14
is proportional to 520
).
To calculate a percent of a number, multiply the number by the decimal equivalent of the percent.
Example: 40% of 600.40 6024
×
450 225
90 600
11
2.1
3.19
30.24
18.69
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Problem solving with percents:
Example 1:
45% of a class with 20 students is boys. How many girls are there?
Method 1: 45% of 20 = number of boys
0.45 × 20 = 9 boys
20 students – 9 boys = 11 girls
Method 2: 45% are boys, which means 100% - 45% are girls
= 55% girls
0.55 × 20 = 11 girls
Example 2:
How much would a 15% tip be on a meal costing $48.50?
15% of 48.50 = 0.15 × 48.50 = $7.28
A 15% tip would be $7.28.
Example 3:
35% of a sport shop’s income is from hockey equipment. Last year the shop sold
$4970 in hockey equipment. What was the shop’s total income?
35% of total income = hockey income
35 4970 7 4970 4970 7 710 20 710 $14 200100 ? 20 ?
= = ÷ = × =
The shop made $14 200 last year.
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Practice
Solve the word problem.
a. Steven got 1420
on a science test and 3650
on a math test. On which test did he score a
higher mark?
b. 18 adults and 30 children go on a field trip. What percent of the group are children?
c. A pair of jeans advertised for $34.97 is 35% off. What is the sale price of the jeans?
d. Calculate the total price of a CD for $9.65, plus 5% tax.
Science: 14 ÷ 20 = 0.7 = 70%
Math: 36 ÷ 50 = 0.72 = 72%
Hescoredhigheronhismathtest.
18 + 30 = 48 people total
30 ÷ 48 = 0.625 = 63%
63%ofthegrouparechildren.
34.97 × .35 = 12.24
34.97 – 12.24 = 22.73.
Thejeanswere$22.73
9.65 × 0.05 = 0.48
9.65 + 0.48 = 10.13
TheCDcosts$10.13.
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
Summary and Practice:
• Usingwhatyoulearned,answerthefollowingquestions.
1. Complete the chart.
Mixed number
Improper fraction
Model
126
263
2. Solve.
a. 2 11 45 2+ =
b. 1 33 22 8+ =
c. − =4 25 15 3
d. − =5 19 26 4
3. Convert the fractions to decimals. Decide if the fractions are >, <, or =.
a. 9 8 11 14
b. 3 10 13 17
4 5 91 4 510 10 10
+ =
4 3 73 2 58 8 8+ =
12 10 25 1 415 15 15
− =
10 3 79 2 712 12 12
− =
> <0.82 > 0.57 0.23 < 0.59
136
318
118
283
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4. Complete the table.
Fraction Decimal Percent
a. 1125
b. 0.23
c. 63%
d. 48%
e. 0.06
f. 39
5. Laura’s curling team won 9 of 17 games. What percent of the games did her teamwin?
6. A bag of jelly beans has 32% cherry flavoured, 45% lemon, and the rest are grapeflavoured. What percent of the jelly beans are grape flavoured?
9 ÷ 17 = 0.529 × 100 = 53%
Shewon53%ofhergames.
100%-32%-45%=23%
23%ofthejellybeansaregrapeflavoured.
0.44
0.63
0.48
0.33 33%
23%
6%
44%
23100
63100
1225
350
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Preview/Review Concepts W1 - Lesson 4 MathematicsGrade7
7. Bob mixes a punch with 3 parts ginger ale and 5 parts fruit juice. What percentageof the punch is ginger ale?
8. Jessica and Nelly both earn commission (a percent of any sales they make) at acomputer store. Last month Jessica earned $825 on sales of $5500 and Nelly earned$800 on $5100 sales. Who has the better commission percent?
9. A drum set usually costs $548.00. A set is on sale at Drummers Dream for 40%off. Drum Discounters offers the same set at 20% off, plus a further 20% off thediscounted price. Which store would have the lowest price?
3 + 5 = 8 parts total
3 ÷ 8 = 0.375 × 100 = 37.5%
Thepunchis37.5%gingerale.
Jessica825 ÷ 5500 = 0.15 × 100 = 15%
Nelly800 ÷ 5100 = 0.157 × 100 = 16%
Nellyhasthebettercommission.
Drummers Dream Drum Discounters
548 × 0.40 = 219.2 548 × 0.20 = 109.6548 – 219.2 = 328.8 548 – 109.6 = 438.4
438.4 × 0.20 = 87.68438.4 – 87.68 = 350.72
$328.80 $350.72
DrummersDreamhasthelowestprice.
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Preview/Review Concepts W3 - Lesson 4 MathematicsGrade7
W3 – Lesson 4: Plots and Plotting on a Cartesian Plane
Objective:
• Icanidentifypartsofacartesianplane.
Cartesian plane
Also called a coordinategrid, the plane is formed when two
perpendicular number lines intersect at 0. The horizontal line is the x-axis,
and the vertical line is known as the y-axis. The point where the two lines
meet is called the origin. Each section of the grid is called a
quadrant (1, 2, 3, and 4).
Quadrant 1
Quadrant 4
Quadrant 2
Quadrant 3
x-axis
y-axis
origin
Preview/Review Concepts W3 - Lesson 4MathematicsGrade7
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Objective:
• Icanplotpointsonacartesianplane.
Ordered Pairs
A point on the plane is located by an ordered pair (x, y).
The first integer (x-coordinate) tells how far to go on the x axis. The second integer (y-coordinate) tells how far to go on the y-axis.
Example: P(-5, 7) means a point labeled P that is 5 units left, and 7 units up.
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
P(-5, 7)
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Preview/Review Concepts W3 - Lesson 4 MathematicsGrade7
Practice:
1. a. Plot and label the following points on the grid below.
A(4, 5) B(-3, -1) C(-2, 4) D(0, 7) E(6, 0) F(3, -6)
b. What is the xcoordinate for point C?
c. What are thecoordinates for theorigin?
d. Which quadrant ispoint B in?
e. What is the ycoordinate for point D?
2. a. What are the coordinates of each point?
i. Q ii. R iii. S
b. Plot each point on the grid.
i. W(0, -15)
ii. Z(30, 0)
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
y
x -20 20 40 -40
20
40
-20
-40
Q
R
S
-2
(0, 0)
Quadrant 3
7
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
A
B
C
D
E
F
(-30, -10) (0, -30) (40, 0)
y
x -20 20 40 -40
20
40
-20
-40
Q
R
S
W
Z
Preview/Review Concepts W3 - Lesson 4MathematicsGrade7
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Objective:
• Icancreateshapesanddesignsusingpointsonacartesianplane.
Example: Points J, K, and L are three points of a parallelogram, what coordinates should point M be to complete the figure?
M(30, 20) would complete the parallelogram.
Practice:
1. a. Draw a closed five sided figure on the grid below.
b. List the coordinates of the vertices for the figure you drew.
y
x -20 20 40 -40
20
40
-20
-40
J
K L
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
Answers will vary.
Answers will vary.
Developed by Alberta Distance Learning Centre ....................................................................................................... 5
Preview/Review Concepts W3 - Lesson 4 MathematicsGrade7
2. Plot and connect the following series of points.
a. Shape A: (2, 1), (2, 9), (9, 9)
b. Shape B: (-5, 1), (-1, 5), (-5, 9), (-9, 5)
c. Shape C: (6, -1), (9, -4), (4, -9), (1, -6)
d. Shape D: (-3, -2), (-5, -4), (-7, -2), (-9, -4), (-5, -8), (-1, -4)
e. What quadrant is shape D in?
f. Is there a way to tell which quadrant shape A would be in before plotting thepoints?
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
-2 -4 -6 6 4 2
2
4
6
-6
-4
-2
x
y
Quadrant 3
Since all the ordered pairs are positive it will be in Quadrant 1.
A
B
DC
Preview/Review Concepts W3 - Lesson 4MathematicsGrade7
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3. Points A, B and C are the vertices of a square, what are the coordinates for point Dthat would complete the square? Plot the coordinate and draw the shape.
4. a. Draw a Cartesian plane using appropriate units for the axes so the following points can be plotted.
b. Plot the following points.
(-10, -10), (-5, 0), (20, -15), (30, 5), (5, 15), (10, 25), (-20, 20)
c. Connect the points in order. Which quadrant is the shape pointing to?
y
x -20 20 40 -40
20
40
-20
-40
B
A
C
y
x -20 20 40 -40
20
40
-20
-40
B
A
C
D
Quadrant 2
y
x -20 20 40 -40
20
40
-20
-40
The coordinates are (20, -40).
Developed by Alberta Distance Learning Centre ....................................................................................................... 7
Preview/Review Concepts W3 - Lesson 4 MathematicsGrade7
1. Fill in the blanks.
a. An ordered pair is in Quadrant 1 when the x coordinate is a ____________integer, and the y coordinate is a ____________ integer.
b. An ordered pair is in Quadrant 2 when the x coordinate is a ____________integer, and the y coordinate is a ____________ integer.
c. An ordered pair is in Quadrant 3 when the x coordinate is a ____________integer, and the y coordinate is a ____________ integer.
d. An ordered pair is in Quadrant 4 when the x coordinate is a ____________integer, and the y coordinate is a ____________ integer.
e. When the x coordinate is equal to 0 the point is in no quadrant because it is onthe ____________.
f. When the y coordinate is equal to 0 the point is in no quadrant because it is onthe ____________.
2. a. Plot the following points.
A(0, 30) B(10, 0)
C(-35, 0) D(-15, -15)
E(-20,-45) F(0, -30)
G(20, -45) H(15, -15)
I(35, 0) J(10, 0)
K(0, 30)
b. Connect the points in order from A to J. Which quadrants have a point of thefigure in them?
y
x -20 20 40 -40
20
40
-20
-40
positive
positive
positivepositive
negative
negative
negativenegative
y axis
x axis
y
x -20 20 40 -40
20
40
-20
-40
Quadrants 3 and 4.
Preview/Review Concepts W3 - Lesson 4MathematicsGrade7
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3. Patrick was playing a game of Battleship with his brother. If his brothers’ shipswere arranged like the image below, what are the three coordinates Patrick needs towin the game? (You are looking for the coordinates of the unmanned ships.)
4. a. Draw a Cartesian plane using an appropriate unit for the axes.
b. Plot the following points.
(30, 50), (30, 130), (10, 130), (10, 90), (-10, 130), (-30, 90), (-30, 130), (-50, 130),(-50, 50), (-30, 50), (-10, 90), (10, 50)
(4, 10)(3, 7) and(6, 3)
y
x -30 30 60 -60
30
60
-30
-60
Developed by Alberta Distance Learning Centre ....................................................................................................... 9
Preview/Review Concepts W3 - Lesson 4 MathematicsGrade7
5. Plot and connect the points of each series.
6
4
2
- 2- 4- 6642
y
x
- 2
- 4
- 6
a. (-3, -2)+(-1, -2) b. (1, -9)+(1, -5)+(3, -9)+(3, -5)
c. (10, 7)+(10, 5) d. (2, 5)+(0, 5)+(0, 9)+(2, 9)
e. (7, 7)+(8, 5) f. (0, 7)+(1, 7)
g. (-5, -9)+(-5, -5)+(-3, -5) h. (0, -2)+(2, -2)+(2, 0)+(0, 0)+(0, 2)+(2, 2)
i. (-5, -7)+(-4, -7) j. (4, 9)+(4, 5)
k. (-10, 9) + (-12, 8) + (-12, 6) + (-10, 5) +(-10, 7)+(-11, 7)
l. (-6, 5)+(-6, 9)+(-4, 9)+(-4, 5)+(-6, 5)
m. (-3, 5)+(-3, 9)+(-2, 6)+(-1, 9)+(-1, 5)
n. (-9, 7)+(-8, 7) o. (9, 9)+(10, 7)+(11, 9)
p. (3, 9)+(5, 9) q. (-3, 2)+(-1, 2)
r. (6, 5)+(6, 9)+(8, 9)+(8, 7)+(6, 7) s. (-2, -5)+(-2, -9)+(0, -9)+(0, -5)
t. (-2, -2)+(-2, 2) u. (-7, 5)+(-9, 5)+(-9, 9)+(-7, 9)
6
4
2
- 2- 4- 6642
y
x
- 2
- 4
- 6
Developed by Alberta Distance Learning Centre ....................................................................................................... 1
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
W3 – Lesson 5: Transformations
Objective:
• Icanmovepointsonacartesianplane.
Translations
Example: A triangle ABC shown below has been moved 6 units to the right and 3 unitsup. If the coordinate of angle B is (-7, -4), what are the coordinates of angle B’.
Answer: Since the slide was (+6, +3), the coordinate for angle B’ is ((-7+6), (-4+3)) or (-1, -1).
Also called a slide, occurs when a figure is moved in one direction in a
straight line from its original position. The final figure is identical to the
original figure.
A
B C
A’
B’ C’
Right 6
Up 3
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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Practice:
1. Translate the figure 2 units to the right and 1 unit down (2, -1).
2. Translate the figure (4, 0).
3. Translate the figure (5, 2).
y
x
y
x
Note: When translating a figure x refers to the horizontal movement. + = right, – = left y refers to the vertical movement + = up, – = down
y
x
Developed by Alberta Distance Learning Centre ....................................................................................................... 3
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
4. Translate the figure (4, -6).
5. Translate the figure (-7, -4).
6. Translate the figure (-3, 3).
y
x
y
x
y
x
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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Objective:
• Icanrotateafigureonacartesianplane.
Rotations
Example 1: A polygon ABCDE, shown below, is rotated 90° counterclockwise around the origin. If point A was originally (4, 6), what is point A’?
Answer: From the point of rotation, the distance to point A is 6 up and 4 across. Rotating the arrows counterclockwise 90° (or +90°,) but still starting from the point of rotation, has the arrows pointing at (-6, -4).
Therefore, point A’ is (-6, -4)
A rotation turns a shape around a point, called point of rotation. The
rotation can be any angle, and can be clockwise (negative), or
counterclockwise (positive).
A
B
C
A’
B’
C’
D
E
D’ E’
Point of rotation
hint: Trace the image onto tracing
paper, put your pencil onto the
point of rotation, and turn the
tracing paper to see the position of
the final image.
Developed by Alberta Distance Learning Centre ....................................................................................................... 5
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
Example 2: A triangle ABC is rotated 180° clockwise around point Q. Draw and label triangle A’B’C’?
Practice:
1. Rotate the figure 90° clockwise about point A.
A’
B’
C’
Q
A
B
C
remember:A circle has 360°.
90° = a quarter turn
180° = a half turn
270° = three quarters turn
y
x
A
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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2. Rotate the figure 180° about point A.
3. Plot the points W(2, 0), X (5, 0), Y (1, 3). Rotate the figure 180° about the origin.
4. Plot A(1, -2), B(0, 2), C(3, 2), D(3, -3). Rotate the figure 90° about the origin.
y
x
y
x A
y
x
W’
B’
D’
W
B
D
X’
A’
X
C
Y’
C’
Y
A
Developed by Alberta Distance Learning Centre ....................................................................................................... 7
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
5. What is the degree of rotation and point of rotation of triangle ABC?
6. What is the degree of rotation and point of rotation of triangle ABC?
y
x
A
A’
B’
C’
B
C
y
x
A
A’
B’
C’
B C
90° about the origin
-90° about the origin
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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Objective:
• Icanreflectafigureonacartesianplane.
Reflections
Example 1: A polygon ABCDE, shown below, is reflected across the x-axis. If point A was originally (0, 6), what is point A’?
Answer: From the line of reflection, the perpendicular distance to point A is 6. Which means point A’ would be 6 units in the opposite direction from the line of reflection.
Therefore, point A’ is (0, -6)
A reflection or flip, creates a mirror image of the shape. The mirror line
would be a line of symmetry for the shape and its image.
Line of reflection
A
B
C
A’
B’
C’
D
E
D’
E’
hint: Trace the image onto tracing
paper including the mirror line. Flip
the paper over and realign the
mirror line to see the position of the
final image.
Developed by Alberta Distance Learning Centre ....................................................................................................... 9
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
Example 2: Draw triangle A’B’C’ when triangle ABC is reflected across line QR.
Practice:
1. Reflect the figure across the y-axis.
Q A
B
C
R
C’
B’ A’
y
x
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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2. Reflect the figure across the x-axis.
3. Reflect the figure across the given line.
4. Reflect the figure across the given line.
y
x
y
x
y
x
Developed by Alberta Distance Learning Centre ....................................................................................................... 11
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
5. Draw the line of reflection.
6. Draw the line of reflection.
y
x
A
A’
B’
C’
B C
y
x
A A’
B’
C’
B C
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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Summary and Practice:
• Usingwhatyou'velearned,answerthefollowingquestions.
1. Fill in the blanks.
a. A word describing a transformation where a figure stays the same except for itslocation is _________________.
b. If point A(5, 0) was translated (2, -1) the new coordinates for A’ would be________.
c. The point that a rotation occurs around is called the ____________________. Itdoes not always have to be the origin.
d. A negative rotation means the image is turned in a __________________ direction.
e. Rotating an image -90° has the same result as rotating it _______°.
f. The line used to create a mirror image is called a ____________________.
g. If point G(-4, 2) was reflected across the y-axis, the coordinates of point G’ wouldbe ______________.
h. If point H(3, -5) was reflected across the x-axis, the coordinates of point H’ wouldbe ______________.
2. Translate the figure (4, 1).
y
x
translation
line of reflection
point of rotation
counterclockwise
A’(7, -1)
G’(4, 2)
H’(3, 5)
270
Developed by Alberta Distance Learning Centre ....................................................................................................... 13
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
3. Translate the figure (-3, -2).
4. Rotate the figure -90° about point A.
5. Rotate the figure 180° about point A.
y
x
y
x
A
y
x A
Preview/Review Concepts W3 - Lesson 5MathematicsGrade7
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6. Reflect the figure across the given line.
7. Draw the line of reflection.
8. Danny created this image of arrows by reflecting itover the y-axis.
a. Would it be possible to make the sametransformation using only a translation? Whyor why not?
b. If Danny wanted to create this image without using a reflection, whattransformation(s) could he use instead?
y
x
y
x
A
A’
B’ C’
B
C
D
D’
No, a translation keeps the imageidentical and will not point the arrow inthe opposite direction.
Because the image is symmetrical, Danny can rotatethe image 180° then translate it into the appropriateposition.
Developed by Alberta Distance Learning Centre ....................................................................................................... 15
Preview/Review Concepts W3 - Lesson 5 MathematicsGrade7
5. Plot and join the coordinates of CDE. C(3, 2), D(-2, 2), E(3, -2).
a. Translate CDE 2 units left and 3 units up to form C’D’E’.
b. Rotate C’D’E’ -90° about the origin forming C”D”E”
6. Plot and join the points to the shape. P(1, 0), Q(4, 0), R(3, 2), S(1, 2).
a. Translate the image 4 units left formingP’Q’R’S’
b. Reflect the image across the x-axis formingP”Q”R”S”. Shade in this figure.
c. Plot figure PQRS again on the second Cartesianplane.
d. Repeat steps a. and b. but start with the reflection,then the translation. (Do step b then step a)
e. Compare the final images. Are they the same? Explain.
y
x
y
x
y
x
Yes the final image is the same since thetransformations were the same. The differencewould be the in between image.
D
P
P
R
R
C
Q
Q
D'
E
S
S
C' D"
P"
P"
R"
R"
P'
P'
R'
R'
Q'
Q'
S'
S'
E'
Q"
Q"
C"
S"
S"
E"
Developed by Alberta Distance Learning Centre ....................................................................................................... 1
Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
W2 – Lesson 4: Statistics
Objective:
• Icanunderstandtermsusedinstatistics.
Collecting Data
Example: Malcolm wanted to know which subject was the most popular at School. He conducted a personal survey asking all the grade 7 students which subject was their favorite. Using tally marks, his data looked like this:
Survey ResultsSubject Tally
MathScienceLanguage ArtsSocial Studies
He used the tally chart to make a frequency table. The table looked like this:
Survey ResultsSubject Tally Frequency
Math 14Science 12Language Arts 8Social Studies 9
Personal Survey: collecting
data in person. Data can also
be collected by mail, telephone,
newspapers, books, or magazines.
Frequency Table: a table
that uses tallies to count the
frequency (number) of data.
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
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Using the database he just created, Malcolm could now create an organized table:
Organized Survey ResultsMath 14Science 12Language Arts 9Social Studies 8
Using the organized results, Malcolm could answer the following questions.
1. Which subject was the most popular? Math
2. Which subject is the least popular? Language Arts
3. What was the sample size (number ofpeople surveyed)?
14 + 12 + 9 + 8 = 43 people
Database: an organized
collection of data or information.
Sample: a selection of the
total information.
Developed by Alberta Distance Learning Centre ....................................................................................................... 3
Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
The data are arranged in alphabetical order
Peanut butter cookies sold the most
Snickerdoodles sold the least
Four boxes of shortbread cookies sold
Three boxes of raisin cookies sold
Practice:
Use the pictograph to answer the following questions.
Cookie SurveyChocolate chip
Gingerbread
Peanut Butter
Raisin
Shortbread
Snickerdoodle
Vanilla
Legend: Each represents one box of cookies sold
1. How are the data in the pictograph arranged?
2. Which cookie sold the most?
3. Which cookie sold the least?
4. What was the frequency of shortbread cookies sold?
5. What was the frequency of raisin cookies sold?
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
....................................................................................................... Developed by Alberta Distance Learning Centre4
10.8
12.4
12.5
16.8
Mean: the arithmetic average.
Objective:
• IcanIcanfindthemeanofasetofdata.
Finding the mean
Example:
Basketball ResultsGame Number 1 2 3 4 5Points scored 24 51 34 22 43
Find the total points over all five games:
24 + 51 + 34 + 22 + 43 = 174
174 points in five games.
Find the mean by dividing the total points by the number of games.
174 ÷ 5 = 34.8 (but since you can’t score 0.8 points in basketball round to 35)
The mean (average) points were 35 per game.
Practice:Find the mean of the following sets of data. Round your answer to one decimal point.
a. 24, 5, 14, 9, 32
b. 11, 5, 8, 6, 20, 15
c. 2, 9, 22, 12, 26, 5, 11
d. 18, 12, 9, 11
How many games:
scored close to 35 points?Only one out of five games.
scored above 35 points?Two out of five games
scored below 35 points?Two out of five games
Developed by Alberta Distance Learning Centre ....................................................................................................... 5
Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
1.3, 1.5, 1.8, ____, 2.1, 2.2, 2.3(1.8 + 2.1) ÷ 2 = 1.95 or 2
11, 23, 34, ___, 44, 56, 62(34 + 44) ÷ 2 = 39
123, 132, 138, 205, 234138
149, 156, 218, ___, 219, 223, 321(218 + 219) ÷ 2 = 218.5
Objective:
• Icanfindthemedianofasetofdata.
Finding the median
Example:
Some prices are listed below, find the median.
$215, $211, $246, $213, $287
Arrange in ascending order:
$211, $213, $215, $246, $287
Since there is an odd number of numbers, the middle number is the median: $215
Example 2:
Find the median of the numbers.
49, 62, 57, 44, 51, 67, 46, 54
Arrange in ascending order:
44, 46, 49, 51, _____, 54, 57, 62, 67
Since there is an even number of numbers, the median will be exactly between the two middle numbers:
(51 + 54) ÷ 2 = 52.5
Practice:
Find the median of the following sets of data.
a. 1.3, 2.1, 1.8, 2.3, 2.2, 1.5 b. 149, 218, 321, 156, 223, 219
c. 23, 56, 34, 11, 44, 62 d. $123, $234, $132, $138, $205
Median: the middle value in a
distribution.
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
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3, 15 ,15, 15, 17, 17, 27, 40, 44, 44Mode: 15
11, 11, 12, 12, 13, 14, 15Mode: 11, 12
22, 23, 24, 32, 32, 33, 34Mode: 32
68, 79, 84, 84, 85, 90, 91, 100Mode: 84
Objective:
• Icanfindthemodeofasetofdata.
Finding the mode
Example:
Steven counted the number of people in the cars that stopped in front of the school. Find the mode.
2 3 1 2 4 4 1 3 4 52 2 2 3 3 2 5 2 1 4
Arrange the numbers in ascending order:
1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5
Count the frequency of each number:
1’s – 3 2’s – 7 3’s – 4 4’s – 4 5’s – 2
The highest frequency is the mode – 2 people in the car
Example 2:
Find the mode of the following numbers.
1, 2, 7, 2, 4, 5, 1, 7
Arrange in ascending order:
1, 1, 2, 2, 4, 5, 7, 7
Since there are three modes, we call this a trimodal distribution.
→ 1, 2, 7 are the three modes.
Practice:Find the mode of the following sets of data.
a. 3, 44, 17 , 17, 44, 15, 15, 15, 27, 40 b. 91, 79, 84, 85, 84, 90, 68, 100
c. 23, 32, 34, 22, 32, 24, 33 d. 11, 12, 15, 13, 12, 11, 14
Mode: the most frequently
occurring value in a set of data.
A data set with no repeated
numbers has no mode.
A data set with two modes is
called a bimodal distribution.
Developed by Alberta Distance Learning Centre ....................................................................................................... 7
Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
Range = 252 – 210 = 42
Range = 40 – 8 = 32 Range = 8 – 2 = 6
Range = 2.3 – 1.1 = 1.2
Objective:
• Icandeterminetherangeofasetofdata.
The rangeExample:
Find the range of 150, 250, 825, 400, 18, and 500
Arrange the numbers in ascending order:
20, 150, 250, 400, 500, 825
Calculate range:
Range = largest value – smallest value = 825 – 20 = 805
The range is 805
Example 2:
A seven day forecast looks like this
Sun Mon Tues Wed Thurs Fri Sat17°C 15°C 20°C 18°C 17°C 18°C 16°C
Find the range of the temperatures
15, 16, 17, 17, 18, 18, 20
Range = largest value – smallest value = 20 – 15 = 5
The temperatures had a range of 5°C during the week.
Practice:Find the range of the following sets of data.
a. 243, 221, 210, 252, 231, 224 b. 1.1, 1.7, 2.3, 1.6, 1.2, 1.4
c. 11, 40, 21, 32, 8 d. 2, 5, 7, 2, 6, 8, 4, 3
range: the difference between
the highest and lowest values.
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
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No, since the accident was a one-time problem, the 45 minute wait should be considered an outlier which makes the wait time less than 5 minutes.
Objective:
• Icananalyzeasetofdatatoidentifyanyoutliers.
Outliers
Example:
A bus company will add another bus if the wait time at a busy bus stop is longer than 5 minutes.
The following numbers represents the time in minutes that people wait at the bus stop.
1, 3, 4, 3, 5, 2, 5, 45, 1, 3, 4, 4, 2, 5, 2, 4, 1, 3, 4, 2
Using this information the mean, median and mode is:
Mean:
(1 + 3 + 4 + 3 + 5 + 2 + 5 + 45 + 1 + 3 + 4 + 4 + 2 + 5 + 2 + 4 + 1 + 3 + 4 + 2) ÷ 20 = 103 ÷ 20 = 5.15 minutes
Median:
1, 1, 1, 2, 2, 2, 2, 3, 3, 3, ____, 3, 4, 4, 4, 4, 4, 5, 5, 5, 45 Median: 3
Mode is 4
The 45 minute wait was because there was an accident on the road. Therefore 45 minutes is an outlier.
If the outlier is removed, the new mean, median and mode is:
Mean:
(1 + 3 + 4 + 3 + 5 + 2 + 5 + 1 + 3 + 4 + 4 + 2 + 5 + 2 + 4 + 1 + 3 + 4 + 2) ÷ 19 = 3.05
Median:
1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5 Median: 3
Mode is 4
Should the bus company add another bus? Explain.
Outliers: a value in a data set
which is far removed in value
from the other data.
Developed by Alberta Distance Learning Centre ....................................................................................................... 9
Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
67.85 = 67.9
71.2
Unfortunately all student in the class must be included as partof the class average.
In this case, the student is no longer part of the class so hermark can be excluded.
Answers may vary. Example: Yes, because Greg has to work for his money. Or, no, it is not uncommon to do chores to get an allowance.
5, 5, 5, 5, 6, 6, 7, 8, 25
Mean: $8Median: $6Mode: $5
Practice:
1. A class average is the mean of all the marks of each student in the class.
Dave’s class has the following scores.
67%, 78%, 59%, 66%, 72%, 5%, 65%, 69%, 68%, 75%,82%, 77%, 73%, 78%, 67%, 78%, 65%, 66%, 62%, 85%
a. Calculate the mean including the outlier.
b. Calculate the mean without the outlier.
c. The school rewards classes with an average above 70%, should the outlier beincluded when reporting this class average?
d. What if the 0% was the result of a student who had moved away, but her namewas still on the class list?
2. Some friends compared the amount of allowance they get. Their allowance eachweek was:
$5, $7, $5, $25, $6, $5, $8, $6, $5
a. What is the mean, median and mode of the allowances?
b. If Greg receives $25 in allowance partly as payment for helping with farm choresevery day, should his allowance be counted as an outlier? Why or why not?
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
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Since most players do not earn $5000 a game, the best average is the median, at $1250, which best represents the rookies and the five-year players.
Objective:
• Icangivereal-worldexampleswherethemean,medianormodeisthemostappropriatemeasuretousewhenreportingfindings.
Deciding which to use, mean/ median/ mode
Example: A sports team has a different contract for all their players. Rookies get $1000 per game, players over 5 years get $1500 a game, and veterans over 10 years get $5000 a game.
The team roster currently has: 6 rookies, 5 five years, and 1 veteran.
Or
1000, 1000, 1000, 1000, 1000, 1000, 1500, 1500, 1500, 1500, 1500, 5000
In a TV interview, the team manager is asked “abouthowmuchdoeseachplayermake?”
If the manager reports the mean:
(1000 + 1000 + 1000 + 1000 + 1000 + 1000 + 1500 + 1500 + 1500 + 1500 + 1500 + 5000) ÷ 12 = $1541
If the manager reports the median:
1000, 1000, 1000, 1000, 1000, 1000, _____, 1500, 1500, 1500, 1500, 1500, 5000= (1000 + 1500) ÷ 2 = $1250
If the manager reports the mode:
1000, 1000, 1000, 1000, 1000, 1000, 1500, 1500, 1500, 1500, 1500, 5000= $1000
Which amount would be the most accurate representation of the players’ earnings? Why?
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Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
Mean = 68%
Median: 74%
Mode: 65%
The median is the best indicator overall of how much Scottunderstands math as a subject.
No, Robin should have used the mean as the average to share the money since it is the value of the bills that is important, not the frequency of each.
Each brother should have gotten $28.80 (rather than $6) whichmeans Robin kept $22.80 from each brother.
Practice:
1. Scott’s math test marks for the year are 65%, 83%, 90%, 84%, 65%, and 21%
a. Calculate the mean
b. Find the median
c. Find the mode
d. If Scott’s parents asked his teacher how Scott was doing which average is thebest representation of what Scott has learned? Why?
2. Robin has some money she has to share with her 4 brothers. The bills she was givenhas are:
1, 1, 1, 1, 5, 5, 5, 5, 20, 100
a. She decides that she will use the modes to distribute the bills, and gives herbrothers each a dollar bill and a five. Is this a fair method to share the money?Why or why not?
b. How much did Robin keep from each of her brothers?
Preview/Review Concepts W2 - Lesson 4Mathematics Grade 7
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Mode, to tell you which size sold the most numbers.
Mean, to see if most of the bags are the same weight.
Mean, to balance out the expensive days with the cheaper days.
Mode, since more people would have smaller salaries.
85.5
$5.52
84
17 – 2 = 15
Summary and Practice:
• Usingwhatyou'velearned,answerthefollowingquestions.
1. Susanne scored 75, 83, 92, 79, 96, and 88 points on her spelling tests. What is heraverage score?
2. If different boxes of cookies cost $4.10, $4.32, $4.79, $5.52, $7.18, $7.92 and $9.58,what is the median price?
3. Find the mode of 68, 77, 79, 84, 85, 84, 90, 91, 93, 100
4. Find the range of the values: 2, 5, 6, 6, 8, 10, 12, 17
5. Which measure (mean, median or mode) would you use to describe each of thefollowing cases? Explain.
a. Size of pants sold in a store, if you wanted to send in an order for more pants.
b. Mass of bags of candy, if you were quality control.
c. Cost of lunch over a one month period, if you were planning next month’s budget.
d. Salary of people in a company with only a few managers and lots of entry levelemployees, if you were trying to prove wages are too low.
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Preview/Review Concepts W2 - Lesson 4 Mathematics Grade 7
Answers will vary. Example: low test score because of not studying
Answers will vary. Example: wrong number measured because theruler was upside down.
I would replace the macaroni and cheese because it is currently the least popular menu item.
2012891417135
Fries 2017141312985
Chicken fingersChicken wrapHotdogPizzaTacosHamburgerMacaroni and cheese98
6. Describe a situation when an outlier should be included when calculating anaverage.
7. Describe a situation when an outlier should not be included.
8. Betty was conducting a survey about the school’s cafeteria menu. She asked peoplein the lunch line what food they liked the most. Her results were:
Survey ResultsFood Item Tally Frequency
FriesPizzaHamburgerTacosChicken wrapChicken fingersHotdogMacaroni and cheese
a. Complete the frequency table.
b. Create an organized table listing foods frommost popular to least popular.
c. What was the sample size of this survey?
If you were to replace an item on the menu, which item would you replace.
Organized Survey Results
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
W2 – Lesson 1: Table of Values and Graphing Linear Equations
Objective:
• Icanusealinearrelationtorepresentapattern.
Finding A Pattern
Figure 1 Figure 2 Figure 3
Question:
What if someone asked you to draw the 9th figure in this series?
Look for the relationship or pattern between the figure numbers and each figure.
→ The only thing that changes arethe number of stars
→ The number of stars is the same as the figure number
→ The moons stay the same in each figure.
Pattern rule:
Figure x = x stars + 3 moons
Answer:
Figure 9: 9 stars + 3 moons
How many stars would Figure 15 have? _______
relation:when two numbers or things
are related in some way.
Example: Canada → Dollar
Japan → Yen
Variable:the part of the pattern that
varies or changes; usually represented
by a letter..
15
Preview/Review Concepts W2 - Lesson 1MathematicsGrade7
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Practice
Figure 1 Figure 2 Figure 3
1. Write a pattern rule for the figures.
2. How many dark tiles would there be in Figure 27?
3. How many total tiles will there be in Figure 13?
Figure x = 4x + 3
27 × 4 = 108
4(13) + 3 = 55 tiles
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
Objective:
• Icancreateatableofvaluesforagivenlinearrelation.
Figure 1 Figure 2 Figure 3
Shape Number(n)
Number of Hexagons(x)
1 3
2 4
3 5
4
5
6
10
24
Creating a pattern rule from a chart
→ The relationship is: shape number + 2
→ The pattern rule: Number of Hexagons x = n + 2
→ Using this pattern rule: Number of Hexagons in Shape number 4 = 4 + 2 = 6
Complete the remainder of the chart using the pattern rule.
6
7
8
12
26
Preview/Review Concepts W2 - Lesson 1MathematicsGrade7
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Practice:
1.
Figure 1 Figure 2 Figure 3
a. What is a possible pattern rule?
b. Complete the table of values using the rule.
2. Use the pattern rule given at the top of the table to complete the tables.
Pattern Number (n)
Number of circles (x)
1 22 43 64 85122537
n = p - 1
PatternNumber(p )
Numberofcircles(n=p-1)
1 023451050
n = 2p
PatternNumber(p )
Numberofcircles(n=2p)
1 223451050
n = 2p - 1
PatternNum-ber(p )
Numberofcircles(n=2p-1)
1 023451050
10
1 4 3
2 6 5
3 8 7
4 10 9
9 20 19
49 100 99
24
50
74
Number of circles in Figure n = 2n
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
Objective:
• Icanusealinearrelationtocreateatableofvaluesandthengraphit
Figure 1 Figure 2 Figure 3
→ The pattern rule: Number of boxes in Fig. x = 2x + 3
→ A table of values for the figures above:
By extrapolating (extending) the line, we can use the graph to predict how many squares would be in other figures. Predict how many squares would be in Fig. 12.
Figure Number
Number of squares
1 52 73 94 115 136 157 178 19
02468
1210
14161820222426
0 1 2 3 4 5 6 7 8 9 10
Nu
mb
er o
f S
qu
ares
Figure Number
27 squares
Preview/Review Concepts W2 - Lesson 1MathematicsGrade7
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Practice:
a. Patrick is arranging tables and chairs for a banquet.
What is the pattern rule describing the number of chairs, c, needed for each number of tables, t?
b. Complete the table, and graph the results
c. If Patrick has 10 tables lined up, how many chairs wouldhe need?
Number of Tables (t)
Number of Chairs (c)
12345678
c = 3t + 4
7
00
2
1 2
4
3 4
6
5 6
8
7 8
10
9 10
1214161820222426283032
10
13
16
19
25
28
22
34
Nu
mb
er o
f C
hai
rs
Number of Tables
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
Objective:
• Icandescribethepatternsfoundinthegraphtodrawconclusions.
Graph each of the following table of values in different colours on the same grid. Make a key to identify each line produced.
a. b.
c. d.
y = n
n y
12345
y = n + 3
n y
12345
y = 2n
n y
12345
y = n - 1
n y
12345
1 4
02
2 5
14
3 6
26
4 7
38
5 8
410
Preview/Review Concepts W2 - Lesson 1MathematicsGrade7
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a. What is the differencebetween graphs a. and b?
b. What is the differencebetween graphs a. and c?
c. What is the differencebetween graphs a. and d?
Same graph 3 spaces higher
Graph c is 2 times steeper.
Same graph 1 space lower
0123456789
1011
y=n
y=n-1
y=2n
y=n+3
0 1 2 3 4 5 6 7 8 9 10
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
Summary and Practice:
• Usingwhatyou'velearned,answerthefollowingquestions.
1. Hilary started with $50 in her piggy bank and saved $5 each week from herallowance.
a. What is the pattern relation that would describe the amount of money (t) in thebank for nweeks?
b. Complete a table of values for this relation, and graph the relation.
Week (n) Money (t)12345
c. After 20 weeks, how much money would Hilary have in the bank?
Total money = 5n + 50
5560657075
5(20) + 50 = $150
0 0 1 2 3 4 5 6 7 8
10
9 10
2030405060708090
100110
Tot
al C
ost
Week
Preview/Review Concepts W2 - Lesson 1MathematicsGrade7
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2. Consider the following graph.
a. What is the relation represented by this graph?
b. The data for input value 3 is missing. What should bethe output value for input value 3?
c. What would be the output value for an input value of20?
3. A pizza with cheese costs $8.50. Each additional topping is $0.50.
a. Write a relation for the cost of a pizza with n number of extra toppings.
b. What is the cost of a pizza with 8 extra toppings?
c. On the first Thursday of the month the pizzas go on sale for $5.00. What wouldthe new relation look like?
d. What is the cost of the 8 topping pizza on the first Thursday of February?
10
1211
13
00 1 2
123
3 4 5 6 7
456789
Out
put V
alue
Input Value
Output value = 2x - 1
Output value = 5
Output value = 39
Cost = 0.5n + 8.50
Cost = 0.5(8) + 8.50 = $12.50
Cost = 0.5n + 5
Cost = 0.5(8) + 5 = $9
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Preview/Review Concepts W2 - Lesson 1 MathematicsGrade7
4. Admission to Wacky World is $6. Each ride is an additional $2.
a. What is the pattern rule showing how total cost is related to the number ofrides?
b. Complete a table of values for this relation, and graph the relation.
Rides (r) Total Cost (c)
12345
c. Circle the point on the graph that would show the total cost of going on 8 rides.
d. If Charles goes into the park with $35, what is the maximum number of rides hecan go on?
Cost (c) = 2r + 6
810121416
00 1 2 3 4 5 6 7 8
2
9 10
468
10121416182022
Tot
al C
ost
Rides
14 rides and $1.00 leftover.35 - 6 = 2929 = 14.52
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
W2 – Lesson 3: Algebra and Verifying Linear Equations
Objective:
• Icansolveandverifythesolutiontoalinearequation.
Solving equations using algebra
Example: 2x + 9 = 13
Undo addition: subtract 9 frombothsidesoftheequalsign.
2x+9-9=13-9
2x=4
Undo multiplication: divide bothsides by 2.
2x 4=2 2
x=2
Example 2: x -4 = 23
Undo subtraction: add 4 to bothsides.
x -4+ 4 = 2+43x = 63Undo division: multiply bothsides by 3.
x ×3 = 6×33x=18
remember: whatever you
do to one side, you do to
the other side too.
To solve an equation, isolate the variable by “undoing” the operations surrounding the variable
Do Un-do+ -- +× ÷÷ ×
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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4x – 2 + 2 = 14 + 2 3n + 5 – 5 = 11 – 5
d = 4w = 5
4x = 16 3n = 6
w + 45 – 45 = 50 – 45 2d – 6 + 6 = 2 + 62d = 8
x = 4 n = 2
Practice:
Solve each equation, showing each algebra step.
a. 4x – 2 = 14 b. 3n + 5 = 11
c. w + 45 = 50 d. 2d – 6 = 2
Verifying a solution
Example: 2x + 9 = 13 Our solution was x = 2.
Verify: Left side: 2(2) + 9 Right side: 134 + 9 13
Since the left side of the equal sign ends up being the same as the right side, we know the solution is correct.
Example 2: x/3- 4=2Our solution was x = 18.
Verify: Left side: (18)/3- 4 Right side: 26 – 42
Verify a solution by substituting the answer back into the original equation.
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
Left side: Left side:
2(9) – 7
(18) - 53
18 – 7 6 – 5 11 1
Right side: 11 Right side: 1
Correct Correct
Left side: Left side:(6) + 32 2(7) + 7
3 + 3 14 + 7 6 21
Right side: 8 Right side: 17
Incorrect Incorrect
Left side: Left side:(20) + 64 6(2)- 11
5+6 12 – 11 11 1
Right side: 11 Right side: 13
Correct Incorrect
Practice:
Verify if the given solution is correct. Show all steps. Note: Some will be incorrect
a. 2x – 7 = 11, x = 9 b. 5 1, 183y y− = =
c. 3 8, 62n n+ = = d. 2d+7=17, d=7
e. 6 11, 204g g+ = = f. 6d-11=13,d=2
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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Unit tile: represented by a single
tile. Each one tile represents +1.
Variable tile: represented by a
long rectangular tile. Each tile
represents one unit of a variable.
Objective:
• Icanverifythesolutiontoalinearequationusingmanipulatives.
Verifying equations with algebra tiles
Solve: x + 4 = 9
Left side: Right side
Remove4unittilesfromeachsidetoisolatethex-tile
Eachx-tileequals5unittiles(x=5)
Verify: x + 4 = 9, x = 5
Left side
Right side
(9 tiles)
→Since the left side has the same number of
tiles as the right side, we know the solution
is correct.
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
Correct
Practice:
Verify each given solution using Algebra tiles.
Verify: x – 2 = 3, x = 5
Left side
Right side
Verify: 2x + 1 = 3, x = 1
Left side
Right side
Verify: 3x – 3 = 6, x = 3
Left side
Right side
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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Objective:
• Icanuseequationstosolvewordproblems.
Writing and solving equations from word problems
Example:At the bakery loaves of bread cost $2.00 per loaf. How many loaves can be bought with $10.00?
a. Write the equation representing the solution.
2b = 10
b. Solve the equation, verify the equation.
2b = 10
2 102 2b=
b = 5
Left side: 2b → 2(5) → 10
Right side: 10
LS = RS, therefore the solution is correct
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
13 + h = 21
2n - 5 = 7
13 -13 + h = 21 - 13h = 8
Verify:
Left side:13 + (8)21
Right side: 21
2n - 5 + 5 = 7 + 52n=12n=6
The mystery number is 6
Practice:
1. In Greg’s class, 13 people play hockey. The class has 21 students.
a. Write an equation to find the number of students who don’t play hockey.
b. Solve the equation, verify the solution.
1. Jake is thinking of a number. He multiplies it by two and then subtracts five. Theresult is seven.
a. Write an equation to represent the solution.
b. Solve the equation to find the mystery number.
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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subtract
add
4
6
multiply 2
divide 3
5x-7=185x-7+7=18+75x=25x=5
4n+8=204n+8-8=20-84n=12n=3
Verify:Left side:5(5)-725-718
Verify:Left side:4(3)+812+820
Right side: 18
Right side: 20
Summary and Practice:
• Icanuseequationstosolvewordproblems.
1. Fill in the blanks.
→ A variable, x, has 4 added to it, we need to _____________ ______ from both sides to isolate x.
→ A variable, n, has 6 subtracted from it; we need to _____________ ______ to both sides to isolate n.
→ A variable, g, is multiplied by 3, to isolate g we need to _____________ by ______ on both sides.
→ A variable, w, is divided by 2; to isolate w we need to _____________ by ______ on both sides.
2. Solve and verify, showing all steps.
a. 5x – 7 = 18
b. 4n + 8 = 20
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
Left side
Right side
2y + 6 – 6 = 16 – 62y = 10y = 5
h + 3 - 3 = 6 - 32h = 32h ×2 = 3×22h = 6
w + 4 – 4 = 11 – 4w = 7
Left side
Right side
Left side
Right side
3. Solve. Verify your solution using Algebra tiles.
a. w + 4 = 11
b. 2y + 6 = 16
c. 3 62h+ =
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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f – 3 = 7
f – 3 + 3 = 7 + 3f = 10
Verify:Left side:(10) – 37
Right side: 7
No, Peter is incorrect because p needs to stand for the number of spaces between the posts not including the gate space.
3 (8) + 524 + 529
He actually needs 29 pieces.
4. Sarah invited some friends over to play video games. Three friends left after onegame, but seven friends stayed to play more. How many friends did Sarah haveover?
a. Write an equation
b. Solve the equation, verify the solution.
5. Peter wants to build a fence around his garden. Heneeds 3 cross pieces between each fence post, exceptthe gate which needs 5 pieces. Before going to thelumber store, Peter determines he will need 3p + 5pieces of wood, where p is the number of posts.
a. If Peter’s garden has 9 fence posts, he decides he’ll need 32 pieces of wood. IsPeter correct? Why or why not?
b. How many pieces of wood does Peter actually need?
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Preview/Review Concepts W2 - Lesson 3 Mathematics Grade 7
c = 4S + 6L
44 = 4S + 6(2)44 = 4S + 1244 – 12 = 4S +12 – 1232 = 4S8 = S
38 = 4S + 6(3)38 = 4S + 1838 – 18 = 4S +18 – 1820 = 4S5 = S
She can have 8 small tables
She can have 5 small tables
She can have 4 large tables
48 = 4(6) + 6L48 = 24 + 6L48 – 24 = 24 – 24 + 6L 24 = 6L4 = L
6. Beth is setting up a restaurant with large and small tables. She decides that eachsmall table will have 4 chairs, and each large table will have 6 chairs.
a. Write an expression for the number of chairs (c) using s for small tables, and l forlarge tables.
b. How many tables of the other size can Beth set up if she has:
i. 2 large tables and 44 chairs?
ii. 3 large tables and 38 chairs?
iii. 6 small tables and 48 chairs?
Preview/Review Concepts W2 - Lesson 3Mathematics Grade 7
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8m +15 = 718m + 15 – 15 = 71 – 15 8m = 56m = 7 It will take 7 months to get 71 songs.
7. Warren has 15 songs downloaded to his MP3 player. He downloads 8 new songseach month. After how many months will Warren have 71 songs?