Post on 27-Dec-2015
Multiplying and Dividing of Fractions
Section 3.4 Pages 123 – 129
Section 3.5 Pages 130 – 136
Quick Review
When we multiply or divide two rational numbers we must always be aware of the signs of the two numbers.
Positive (x or ) positive = positive
Positive (x or ) negative = negative
Negative (x or ) positive = negative
Negative (x or ) negative = positive
This would be a good chart to copy down!
Reminder:
1
2
1
2
1
21
2
1
2
Multiplying Simple Fractions- Finding the Product
To multiply two simple fractions, complete the following steps. 1. Multiply the numerators. 2. Multiply the denominators. 3. Reduce the product. 4. Identify the resulting sign on the question
( -/+)
5. Reduce to lowest terms!!!
3 2
5 3
Example 3 2
5 3
6
15
2
5
Try ME:
5
12
2
9
8
12
4
7
Multiplying a Whole Number and a Fraction – Finding the Product
To multiply a whole number and a fraction, complete the following steps. 1. Convert the whole number to a
fraction. 2. Multiply the numerators. 3. Multiply the denominators. 4. Reduce the product. 5. Identify the resulting sign ( -/+)
Try ME:
2 3
4
7
8 3
What about mixed numbers?
If a question contains a mixed number, simply convert it to an improper fraction and… 1. Multiply the numerators. 2. Multiply the denominators. 3. Reduce the product. 4. Identify the resulting sign ( -/+)
Try ME:
62
3
15
6
22
5
35
9
Multiplying Rational Numbers in Decimal form
1. Predict the sign ( +/-)
2. Using compatible numbers to solve the question
3. Place the correct number of decimal places into your product
Try ME:
(-0.4)( -0.7) (0.5)(- 2.4)
Dividing Simple Fractions- Find the Quotient
To divide one fraction by a second fraction, convert the problem to multiplication and multiply the two fractions. 1. Change the second fraction to its
reciprocal 2. Multiply the numerators. 3. Multiply the denominators. 4. Reduce the quotient. 5. Identify the sign result of the question
(+/-)
What is a reciprocal?
Reciprocal The numerator and denominator are switched.
OR the fun way to remember it…
What is a reciprocal?
4
5
5
4
Reciprocal:A fraction doinga handstand!
Try ME:
3
2
6
7
7
9
9
4
Dividing Fractions with Mixed Numbers
To divide a fraction by a whole number: 1. Convert the mixed number to an
improper fraction. 2. Change the second fraction to the
reciprocal 3. Multiply the numerators. 4. Multiply the denominators. 5. Reduce the quotient. 6. Identify the sign result of the question
(+/-) Just like in multiplication, convert all mixed numbers to improper fractions
before dividing!
Try ME:
33
5
2
5
6
6
1
2
2
9
10
Pg.127-129 1,2,7,9,11,12,14,16
Pg.134-136 3,9,12,14, 21
Homework
See the Worksheets that accompany these sections.