Fractions XIVFractions XIVMultiplication of Multiplication of

FractionsFractions

Created by: Mrs. YuskaitisCreated by: Mrs. YuskaitisPresented by: Mr. McCarthyPresented by: Mr. McCarthy

Times You Would Multiply a Times You Would Multiply a Fraction Times a FractionFraction Times a Fraction

Your family eats 1/8 of 1/2 of Your family eats 1/8 of 1/2 of a left a left over wedding cake. over wedding cake.

1/8 of 1/2 or 1/8 x 1/21/8 of 1/2 or 1/8 x 1/2

Times You Would Multiply a Times You Would Multiply a Fraction Times a FractionFraction Times a Fraction

Jose had already read 1/2 of his Jose had already read 1/2 of his novel. Today he read 1/12 of the novel. Today he read 1/12 of the 1/2 left. How much of the book has 1/2 left. How much of the book has he read?he read?

1/12 of 1/2 or 1/12 x 1/21/12 of 1/2 or 1/12 x 1/2

Multiplying FractionsMultiplying FractionsConceptual UnderstandingConceptual Understanding

When you multiply two fractions When you multiply two fractions that are between 0 and 1 the that are between 0 and 1 the product is smaller than both product is smaller than both fractions.fractions.

½ x ¾ = 3/8 Look at the diagram on the next slide to understand why.

Multiplying FractionsMultiplying FractionsConceptual UnderstandingConceptual Understanding

½ x ¾ = 3/8 ¼ ¼ ¼ ¼

1/8 1/8 1/8

How to Find a Fraction How to Find a Fraction of a Fractionof a Fraction

The first thing to remember is “of” The first thing to remember is “of” means multiply in mathematics.means multiply in mathematics.

of = x

How to Find a Fraction How to Find a Fraction of a Fractionof a Fraction

Step 1 - When you see a fraction problem Step 1 - When you see a fraction problem you know when you read “of” in the you know when you read “of” in the problem you multiply.problem you multiply.

ofx12

49

How to Find a Fraction of a How to Find a Fraction of a FractionFraction

Step 2 – Multiply your Step 2 – Multiply your numerators straight across.numerators straight across.

x 49

12 = 4

How to Find a Fraction of a How to Find a Fraction of a FractionFraction

Step 3 – Then multiply your Step 3 – Then multiply your denominators straight across.denominators straight across.

x 49

12 = 4

18

How to Find the Fraction How to Find the Fraction of a Fractionof a Fraction

Step 4 – Simplify your answer. Step 4 – Simplify your answer. In this case we reduce.In this case we reduce.

x 49

12 = 4

18÷÷

22= 2

9

Multiply and SimplifyMultiply and Simplify

95

16

= 930 10

3ofx ÷÷

33

=

Multiply and SimplifyMultiply and Simplify

34

89

= 2436 3

2ofx ÷÷1212

=

Multiply and SimplifyMultiply and Simplify

43

72 = 28

6 6)284ofx

2444 4

6÷÷22 = 2

34

Multiply and SimplifyMultiply and Simplify

92

34 = 27

8 8)273ofx

243

38

Multiply and SimplifyMultiply and Simplify

82

73 = 56

6 6)569ofx

542

26

9 26

÷ 22

=9 13÷

Multiply and SimplifyMultiply and Simplify

34

42 = 12

8 8)121ofx84

48

1 48

÷ 44

= 1 12÷

Super job!

CreditsCredits

Clipart from “Microsoft Clip Gallery” located on the Internet at http://cgl.microsoft.com/clipgallerylive/default.asp