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LESSON 5-3Warm Up

ALGEBRA READINESS

LESSON 5-3Warm Up

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“Multiplying Rational Numbers” (5-3)

How do you multiply fractions?

How do you model the multiplication of fractions?

To multiply fractions together, multiply the numerators and denominators together separately. If the numerator and denominator have common factors, you can simplify them before multiplying.

Example:

Multiply the numerators and denominators together separately. Since 2 and 8 have a GCF,

2, simplify by dividing by 2

Multiply the numerator.

Multiply the denominatos.

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Find • – . 47

512

Divide the 4 and 12 by their GCD, 4.47

512 • – = – 5 • 4

12 • 7

1

3

Simplify.= –5

21

= – 5 • 13 • 7

Multiply the numerators.Multiply the denominators.

Multiplying Rational NumbersLESSON 5-3

Additional Examples

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“Multiplying Rational Numbers” (5-3)

How do you write a decimal as an improper fraction?

To write a decimal as an improper fraction, write the decimal as a mixed number first. Then, change the mixed number into an improper fraction.

Example: Change 4.8 to a fraction.

4.8 = 4 4.8 is read “four and eight tenths”. The fractions form of that is 4 .

4 = Multiply the whole number and the denominator (number of parts in a whole) together to find the number of parts in 4 wholes. Then, add the other 8 parts from of the fraction.

810 8

10

4 x 10 + 8 10

810

48 10

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A gear on a machine makes of a turn in one minute.

How many turns does this gear make in 4.8 minutes?

The gear makes 3 turns in 4.8 minutes.15

23

4.8 • = • Write 4.8 as an improper fraction.23

23

245

Divide 24 and 3 by their GCD, 3.23

245= •

1

8

Multiplying Rational NumbersLESSON 5-3

Additional Examples

= 8 • 25 • 1

Multiply the numerators.Multiply the denominators.

Simplify.165

=

Write the improper fraction as a mixed number.= 315

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“Multiplying Rational Numbers” (5-3)

How do you raise a fraction to a power?

To raise a fraction to a power, multiply the numerator and denominators by themselves the number of times the exponent tells you to.

Example:

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Simplify 3.

Multiplying Rational NumbersLESSON 5-3

Additional Examples

= 125216

Multiply the numerators.Multiply the denominators.

56

56

56 = • •

56 The base is .5

656

3

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4981

6.3

58

35

34

–

58

• 45

– )(

79( )

2

45( )

4

38

–

12

–

256625

Multiplying Rational NumbersLESSON 5-3

Lesson Quiz

Find each product. Simplify.

1. •

2. 8.4 •

3.

Simplify each expression.

4.

5.