SiriusLesson 3 Multiplying and dividing Rational numbers

Multiplying and Dividing Rational Numbers

Sirius Lesson 3
STAAR Review

Open Ended

Give me an example of a rational number.

Multiplying Fractions

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Multiply

3/4 ⋅ 5/8

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Multiply

2/3 ⋅ 1/7

Open Ended

How can we multiply fractions and mixed numbers?

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Multiply

2½ ⋅ 4⅕

Simplify your answer

Open Ended

How do we multiply a whole number by a fraction?

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Multiply

6 ⋅ 4/5

Dividing fractions

Keep Change Flip

To divide fractions, we multiply by the fractions reciprocal.

Fill in the Blanks

Divide the following fractions

3/8 ÷ 5/7

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Divide

6/11 ÷ 3 2/3

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Divide

15 ÷ 2 1/4

Multiplying Decimals

Key Things to Remember

• Start multiplying with the right digit of the second factor. At each step, move one place to the left.

• Disregard decimal points when you multiply.

• The number of decimal places in the product is the total nubmer of decimal places in the original factors.

​So, 2.7 ⋅ 0.384 =1.0368

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Multiply

12.4 ⋅ 0.68

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Divide

149.4 ÷ 33.2

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Divide

779.7 ÷ 34.5

Open Ended

How do you divide a fraction by a decimal?

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Write the fraction as a decimal.

4/5

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Write the following fraction as a decimal.

7/10

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Write the following fraction as a decimal.

1/2

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Write the decimal as a fraction.

0.75

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Write the decimal as a fraction.

0.3

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Write the decimal as a fraction.

0.6

Multiple Choice

One gallon of orange juice costs $3.40. The Javier family drank 2/5 of a gallon of orange juice this morning. What is the cost of the orange juice they drank?

• $2.04

• $8.50

• $1.36

• Not here