Why the Fraction Division Technique WorksDate: 11/27/2004 at 15:46:38 From: Julia Subject: (no subject) Why do we need to flip the second fraction when we divide fractions? For example: (1/2) / (2/3) = 1/2 x 3/2 = 3/4 I am not confused about dividing fractions, but all these years I have wondered why we need to flip the second fraction when we are dividing. Date: 11/29/2004 at 12:22:28 From: Doctor Roy Subject: Re: (no subject) Hi Julia, Thanks for writing to Dr. Math. We aren't _really_ flipping the second fraction, but it is a useful mnemonic device. We are really multiplying by 1: (1/2) / (2/3) = [(1/2) / (2/3)] * 1 = [(1/2) / (2/3)] * [(3/2) / (3/2)] = [(1/2) * (3/2)] / [(2/3)*(3/2)] = [(1/2) * (3/2)] / 1 = [(1/2) * (3/2)] = (1/2) * (3/2) The end result is the same as if we flipped the second fraction, but the full process (entirely written out) shows that it is really multiplying by 1 (in a different way). Does this help? Please feel free to write back with any questions you may have. - Doctor Roy, The Math Forum http://mathforum.org/dr.math/ Date: 11/29/2004 at 22:05:37 From: Julia Subject: Thank you ((no subject)) Thank you very much for your help and time to answer this question. Now I fully understand the concept of why we need to flip the second fraction when we are dividing. |
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