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Multiplying Fractions Get ready to become an expert at multiplying fractions & mixed numbers!

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Presentation on theme: "Multiplying Fractions Get ready to become an expert at multiplying fractions & mixed numbers!"— Presentation transcript:

1 Multiplying Fractions Get ready to become an expert at multiplying fractions & mixed numbers!

2 The Good News? Multiplying fractions is SO much easier than adding or subtracting. No common denominators are involved! How great is that? As long as you know basic multiplication facts and how to simplify fractions, you will be able to multiply fractions without a problem!

3 The Bad News? Some students have been taught (or just believe) that you “cross multiply” fractions. That isn’t true! Cross reduce? Absolutely! Cross multiply? Never!

4 When you multiply by a number less than 1, but greater than 0… A number that is less than 1, but greater than 0 is a proper fraction. When multiplying by a proper fraction, you are actually making the number smaller because you are breaking it down into smaller parts.

5 Multiplying by whole numbers results in a larger number, like this! 5 x 2 = 10 However, multiplying by a fraction results in a smaller number. When you take a fraction of something (like half of a candy bar) you are taking less than the original amount! Multiplying results in smaller numbers? X = We start with ¼ of something and only want ¾ of that ¼. We only want a part of it!

6 What are the steps? To multiply fractions : 1.Cross reduce if possible. 2.Multiply straight across. 3.Simplify if necessary. numerator x numerator denominator x denominator

7 x Click through to see how you solve this type of problem. Example: 1. Cross reduce if possible. 3 and 12 can both be divided by x 2. Multiply straight across. 3. Simplify if necessary (not in this case). 1 28

8 Solve: x Solve on your own. Click through to see the answer! 1. Cross reduce. 3 and 9 can both be divided by Multiply straight across. 3. Simplify if necessary (not in this case) x 4 15

9 Solve: x Solve on your own. Click through to see the answer! 1. Cross reduce if possible. (not in this case). 2. Multiply straight across. 3. Simplify if necessary (not in this case) x 7 40

10 Solve: x Solve on your own. Click through to see the answer! 1. Cross reduce if possible. 2 and 6 can both be divided by Multiply straight across. 3. Simplify if necessary (not in this case) x 5959

11 Are Mixed Numbers the Same? Multiplying mixed numbers is not exactly the same as multiplying fractions. There is one extra step! You can’t just multiply the whole numbers and then multiply the fractions. So what do we do?

12 Multiplying Mixed Numbers Steps : 1.Turn mixed numbers into improper fractions. 2.Cross reduce if possible. 3.Multiply straight across. 4.Simplify if necessary. numerator x numerator denominator x denominator

13 x 3 Do you remember how to turn a fraction into a mixed number? 1.Multiply the denominator by the whole number. 2. Add the numerator onto the product. 3. Write the sum as the new numerator. Keep the denominator the same. Yes, I remember. I can skip this part! Oops, I forgot. Show me how! xx x

14 Click through to see how you solve this type of problem. Example: 2. Cross reduce if possible. 9 and 9 can be divided by 9. 4 and 32 can be divided by x 3. Multiply straight across. 4. Simplify if necessary x 3 1. Turn mixed numbers into improper fractions x = 8

15 Click through to see how you solve this type of problem. Solve: 2. Cross reduce if possible. 5 and 15 can be divided by x 3. Multiply straight across. 4. Simplify if necessary x 7 1. Turn mixed numbers into improper fractions x =

16 Click through to see how you solve this type of problem. Solve: 2. Cross reduce if possible. 10 and 2 can be divided by x 3. Multiply straight across. 4. Simplify if necessary x 3 1. Turn mixed numbers into improper fractions x =

17 Click through to see how you solve this type of problem. Solve: 2. Cross reduce if possible. (Not in this case) x 3. Multiply straight across. 4. Simplify if necessary x 2 1. Turn mixed numbers into improper fractions x =


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