Warm Up

1
Warm Up
Warm Up Write each number as an improper
fraction.
2
7
1
1.
3.
2
2.
3
1
3
8
5
2
3
4.
6
5.
5
3
8
2
Multiplying Rational Numbers

• Section 2.4

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Objectives

• Multiply rational numbers and take positive
  rational numbers to whole-number powers.
• (NS 1.2)

4
In words

• To multiply two fractions, multiply the
  numerators to get the numerator of the product
  and multiply the denominators to get the product.

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Multiplying Fractions

• Multiply numerators denominators.
• Simplify if needed.

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Multiplying Fractions with Mixed Numbers

• Rewrite as improper fraction.
• Multiply numerators denominators.
• Simplify.

If you can, cross cancel!
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Try these on your own
1.
6 7
1 8
3.
3 5
5 8

3 28
2.
4.
2 3
1 2
4 7
7 8

4

1 2


8
Application
1 7
Mark runs mile each day. What is the
total distance Mark runs in 5 days?
(5)


5 7
Mark runs mile in 5 days.
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How do you multiply fractions?
10
Multiplying by a Whole Number

• Rewrite 10 as fraction
• Multiply numerators and multiply denominators.
• Reduce top and bottom
• Simplify

2
11
Multiplying Decimals

• To multiply decimals, first multiply as you would
  with integers.
• The number of decimal places in the product is
  equal to the sum of the number of decimal places
  in the factors.

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Multiplying Decimals
A. 2(0.51)
0 decimal places
2
2 decimal places
? 0.51
0 2 2 decimal places.
1.02
B. (0.4)(3.75)
3.75
2 decimal places
? -0.4
1 decimal place
1.500
2 1 3 decimal places
or 1.5
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Try these on your own
A. 3.1(0.28)
3.1
? 0.28
0.868
B. (0.4)(2.53)
0.4
? 2.53
1.012
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Lets practice
1)
4)
2)
5)
3)
6)
15
How you do you multiply decimal?
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Lesson Quiz
1 7
1.
9
5 8
2 3
2.

1.034
3. 0.47(2.2)
1 2
4. Evaluate 2 (x) for x .
2
8 9
Edgar runs mile each day. What is the total
distance that Edgar runs in a 7-day week?