Presentation on theme: "We have added and subtracted fractions. In this lesson we will multiply fractions. When we add and subtract fractions, we count how many of the same size."— Presentation transcript:
We have added and subtracted fractions. In this lesson we will multiply fractions. When we add and subtract fractions, we count how many of the same size parts there are. When we multiply fractions, the sizes of the parts change. Consider this multiplication problem: How much is one half of one half?
How much is one-half of one-half? Using a fraction manipulative, we show one-half of a circle. To find one- half of one- half, we divide the half in half. Written out the Problem looks like this: 1 1 1 2 2 4 X = We see this equals one- fourth.
What fraction is one half of three fourths? Using a fraction manipulative, we show three fourths of a circle. To find one half of three fourths, we divide each fourth in half. Since one half of one fourth is one eighth, one half of three fourths is three eighths. We may also find one half of three fourths by multiplying. 1 3 3 2 4 8 X = EXAMPLE 1:
Multiply: We find two thirds of four fifths by multiplying. 2 4 3 5 X = EXAMPLE 2: 2 4 8 3 5 15 X = Now You’re Cooking!
3/5 x 1/2 Now that you know how to multiply fractions, let’s try some together. 1/3 x 2/3 2/93/10 2/3 x 2/3 4/9 1/2 x 2/2 2/4 3/4 x 1/2 3/8 1/2 x 1/3 1/6 1/2 x 1/4 1/8
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