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Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion


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September 22nd, 2008, 10:29 AM   #1
 
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Multiplying 3 or more fractions..

How do you multiply three or more fractions at a time?

Example: 2 1/2 x 4 x 3/5?

I know that 4 becomes a reciprocal.

2 1/2 x 4/1 x 3/5?

What do you do after this?
cafegurl is offline  
 
September 22nd, 2008, 12:11 PM   #2
 
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Re: Multiplying 3 or more fractions..

Be careful with your notation there. The reciprocal of a number is 1/number. So the reciprocal of 4 is 1/4...

Anyway,
Make all of the numbers improper fractions:
2 1/2 x 4 x 3/5 -> 5/2 x 4/1 x 3/5

Then multiply the numerators and multiply the denominators:
5*4*3 = 60
2*1*5 = 10

The product of the numerators becomes the new numerator and the product of the denominators becomes the new denominator:
60/10

Then reduce:
6
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