Lesson 45 Multiplying and Dividing Rational Numbers

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Lesson 4-5Multiplying and Dividing Rational
Numbers
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Learning Objectives

• To multiply rational numbers
• To divide rational numbers.

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Rational Numbers

• The term Rational Numbers refers to any number
  that can be written as a fraction.
• This includes fractions that are reduced,
  fractions that can be reduced, mixed numbers,
  improper fractions, and even integers and whole
  numbers.
• An integer, like 4, can be written as a fraction
  by putting the number 1 under it.

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Multiplying Fractions

• Change any mixed numbers into improper fractions.
• Change any whole numbers into improper fractions
  by putting 1 under the whole number.
• Cross cancel wherever possible.
• Multiply horizontally.
• Reduce if necessary.

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Multiplying Fractions
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Multiplying Mixed Numbers

• To multiply mixed numbers, convert them to
  improper fractions first.

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Try These
Multiply the following fractions and mixed
numbers
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Dividing Fractions

• When dividing fractions, they do NOT need to
  have a common denominator.
• - To divide two fractions, change the operation
  to multiplication and take the reciprocal of the
  second fraction (flip the second fraction).
  Keep-Switch-Flip.

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Try These

• Divide the following fractions mixed numbers

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Reciprocals

• Two numbers whose product equals 1 are called
  reciprocals, or multiplicative inverses.