Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
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Warm Up Write each number as an improper
fraction.
1
7
2
1.
2
2.
3.
1
3
3
8
5
2
3
4.
5.
6
5
3
8
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Problem of the Day The sum of three consecutive
integers is 168. What are the three integers?
55, 56, and 57
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Learn to multiply fractions, mixed numbers, and
decimals.
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Notice that multiplying a fraction by a whole
number is the same as multiplying the whole
number by just the numerator of the fraction and
keeping the same denominator.
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RULES FOR MULTIPLYING TWO RATIONAL NUMBERS
If the signs of the factors are the same, the
product is positive.
() () () or () () ()
If the signs of the factors are different, the
product is negative.
() () () or () () ()
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Additional Example 1A Multiplying a Fraction and
an Integer
Multiply. Write the answer in simplest form.
6 7
8
Multiply.
Simplify.
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Additional Example 1B Multiplying a Fraction and
an Integer
Multiply. Write the answer in simplest form.
1 3
2
5
Multiply.
Simplify.
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Check It Out Example 1A
Multiply. Write the answer in simplest form.
5 8
3
Multiply.
Simplify.
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Check It Out Example 1B
Multiply. Write the answer in simplest form.
2 5
4
9
Multiply.
Simplify.
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(No Transcript)
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Additional Example 2A Multiplying Fractions
Multiply. Write the answer in simplest form.
6 7
1 8
Multiply numerators.
Multiply denominators.
Look for common factors 2.
Simplify.
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Additional Example 2B Multiplying Fractions
Multiply. Write the answer in simplest form.
9 2
2 3

Multiply numerators.
Multiply denominators.
Look for common factors 2, 3.
Simplify.
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Check It Out Example 2A
Multiply. Write the answer in simplest form.
5 8
3 5
Multiply numerators.
Multiply denominators.
Look for common factors 5.
Simplify.
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Check It Out Example 2B
Multiply. Write the answer in simplest form.
4 7
7 8

Multiply numerators.
Multiply denominators.
Look for common factors 4, 7.
Simplify.
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Additional Example 3 Multiplying Decimals
Multiply.
A. 2(0.51)
Product is negative with 2 decimal places.
2 (0.51) 1.02
B. (0.4)(3.75)
Product is positive with 3 decimal places.
(0.4) (3.75) 1.500
1.5
00
You can drop the zeros after the decimal point.
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Check It Out Example 3
Multiply.
3.1 (0.28)
A.
Product is positive with 3 decimal places.
3.1 (0.28) 0.868
(0.4)(2.53)
B.
Product is positive with 3 decimal places.
(0.4) (2.53) 1.012
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Additional Example 4 Application
1 20
(7)
Write as an improper fraction.

Multiply.

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Check It Out Example 4
1 7
Mark runs mile each day. What is the total
distance Mark runs in a 5-day week?
(5)
Write as an improper fraction.

Multiply.

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Lesson Quiz
Multiply.
1 7
1.
9
5 8
2 3

2.
1.034
3. 0.47(2.2)
1 2
45
2
4. Evaluate 2 (x) for x .
Edgar runs mile each day. What is the total
distance that Edgar runs in a 7-day week?
5.