1. Multiplication of Fractions
by Mrs. Tumminello

2. Times You Would Multiply a Fraction Times a Fraction
Your family eats 1/8 of 1/2 of a left over wedding cake.
1/8 of 1/2 or 1/8 x 1/2
Copyright © 2000 by Monica Yuskaitis

3. Times You Would Multiply a Fraction Times a Fraction
Jose had already read 1/2 of his novel. Today he read 1/12 of the 1/2 left. How much of the book has he read?
1/12 of 1/2 or 1/12 x 1/2
Copyright © 2000 by Monica Yuskaitis

4. Multiplying Fractions Conceptual Understanding
When you multiply two fractions that are between 0 and 1 the product is smaller than both fractions.
½ x ¾ = 3/8
Look at the diagram on the
next slide to understand why.
Copyright © 2000 by Monica Yuskaitis

5. Multiplying Fractions Conceptual Understanding
½ x ¾ = 3/8
1/8
1/8
1/8
Copyright © 2000 by Monica Yuskaitis

6. Multiplying Fractions

7. We use a fraction square to represent the fraction .
We will think of multiplying fractions as finding a fraction of another fraction. 3 4
We use a fraction square to represent the fraction . 3 4

8. Then, we shade of . We can see that it is the same as .2 3 3 4
Then, we shade of We can see that it is the same as 6 12
But, of is the
same as 2 3 3 4 3 4 2 of 2 3 3 4 X
So, 6 12 = 3 4 X 2

9. How to Find a Fraction of a Fraction
The first thing to remember is “of” means multiply in mathematics. of x =
Copyright © 2000 by Monica Yuskaitis

10. How to Find a Fraction of a Fraction
Step 1 - When you see a fraction problem you know when you read “of” in the problem you multiply. 1 4 x of 2 9
Copyright © 2000 by Monica Yuskaitis

11. How to Find a Fraction of a Fraction
Step 2 – Multiply your numerators straight across. 1
x 4 4 = 2 9
Copyright © 2000 by Monica Yuskaitis

12. How to Find a Fraction of a Fraction
Step 3 – Then multiply your denominators straight across. 1
x 4 4 = 2 9 18
Copyright © 2000 by Monica Yuskaitis

13. How to Find the Fraction of a Fraction
Step 4 – Simplify your answer. In this case we reduce. 1
x 4 4 2 2 ÷ = = 2 9 18 2 9 ÷
Copyright © 2000 by Monica Yuskaitis

14. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify 1 9 9 3 3 of ÷ x = = 6 5 30 3 10 ÷
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15. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify 8 3 24 12 2 of x ÷ = = 9 4 36 12 3 ÷
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16. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify 4 7 4 28 of x = 6) 28 2 3 6 24 4 2 2 ÷ 4 4 = 4 6 2 3 ÷
Copyright © 2000 by Monica Yuskaitis

17. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify 3 3 9 27 3 8 of x = 8) 4 2 8 27 24 3
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18. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify 2 7 8 56 9 6 of x = 6) 3 2 6 56 54 2 2 1 ÷ 9 = 9 2 6 ÷ 2 3
Copyright © 2000 by Monica Yuskaitis

19. Copyright © 2000 by Monica Yuskaitis
Multiply and Simplify
Super job! 4 4 3 12 1 8 of x = 8) 2 4 8 12 8 4 4 1 ÷ = 1 1 4 8 4 2 ÷
Copyright © 2000 by Monica Yuskaitis

20. Now that you know how to multiply fractions, let’s try some together.
1/3
x 2/3
3/5
x 1/2
2/3
x 2/3
2/9
3/10
4/9
3/4
x 1/2
1/2
x 1/3
1/2
x 1/4
1/2
x 2/2
3/8
2/4
1/6
1/8

21. Copyright © 2000 by Monica Yuskaitis
Credits
Clipart from “Microsoft Clip
Gallery” located on the Internet at
clipgallerylive/default.asp
Copyright © 2000 by Monica Yuskaitis