SEPTEMBER 9, 2015

Warm-Up:1. Convert to a fraction.

2. Convert to a mixed number.

3. Write in simplest form.

4. Write a fraction that is equivalent to .

534

4

25

18

4

7

3

235

146

29

, , ,6 9 12

...19 21 284

TONIGHT’S HOMEWORK

Worksheet 1.3

WRITE THE OBJECTIVE IN YOUR OWN WORDS IN YOUR MATH JOURNAL:

SWBAT add or subtract fractions with like and unlike denominators.

Lesson 1.3

VOCABULARY

Least Common MultipleThe smallest non-zero multiple that is common to two or more numbers.

Least Common DenominatorThe least common multiple of two denominators.

EXAMPLE 1

a. Find the least common multiple of 8 and 12:

One method for finding the least common multiple is to list out the multiples of each number until the same number appears on each list.

Multiples of 8: 8, 16, 24, 32, 40, …

Multiples of 12: 12, 24, 36, 48, …

The LCM is 24.

EXAMPLE 1 CONTINUED…b. Find the least common multiple of 4 and 5:Another method to find the LCM is to choose the largest number, in this case 5, and look at its multiples.

Multiples of 5: 5, 10, 15, 20, 25, 30, 35, …

Find the smallest multiple that 4 divides into evenly.

5 – NO10 – NO15 – NO20 – YES (20 4 = 5)

The LCM is 20.

ADDING AND SUBTRACTING FRACTIONS

1. If denominators are not equal, rewrite the fractions as equivalent fractions with common denominators using the least common denominator.

2. Add or subtract the numerators.

3. Write the sum or difference over the common denominator.

4. Write the fraction in simplest form.

EXAMPLE 2

Find the value of .

These fractions already havea common denominator.Add the numerators.

Write in simplest form.

1 710 10

1 7 1 7 810 10 10 10

1 7 810 10

EXAMPLE 3

On Monday, the New Orleans International Airport reported inch of rain. On Tuesday it rained inch. What was the total rainfall for these two days?

The least common multiple of

8 and 16 is 16. Write as an

equivalent fraction with a

denominator of 16.

Write the sum over the LCD.

Change from an improper faction

to a mixed number.

116

6 11 171

16 16 16

EXAMPLE 4

Find the value of .

The least common multiple of

3 and 4 is 12. Write each fraction

as equivalent fractions with a

denominator of 12.

Write the difference over the LCD.

2 13 4

12

5

12

3

12

8

Explore! Fraction Careers

In each step you will perform a calculation that might be done in a certain career. Determine the solution to each step and then guess in what career you might do that specific calculation.

Textbook Page 13

Step 1 = Whole GroupStep 2 = Person AStep 3 = Person BStep 4 = Person CStep 5 = Person D

Each person should explain their answer when the group is finished

EXIT PROBLEMS

Write each answer in simplest form.

1.

2.

3.

4.

4 1

5 10

1 3

2 8

2 33 4

19 1

20 5

910

18

5121

34