Date: 18 Mar 1995 23:31:33 -0500 From: Janet Lowe Subject: Question on fractions Dear Dr. Math, My class would like a explanation on why you invert and multiply when dividing fractions. Thanks! 5TH Graders at Kohl Elementary Janet Lowe Boulder Valley Public Schools
Date: 20 Mar 1995 11:16:46 -0500 From: Dr. Sydney Subject: Re: Question on fractions Hello! We are glad you wrote to us with your question. You asked why you invert and multiply when dividing fractions, but, actually whether you realize it or not, you also invert and multiply when you are dividing whole numbers. For instance, if you were to divide 2 by 3, you would write 2/3, right? Well, that really is the same thing as multiplying 2 by 1/3 (the inverse of 3), because 2 times 1/3 is 2/3. Do you see? So, you might ask, why do you invert and multiply when dividing numbers. This is because when you are dividing 2 numbers, you can always write the fraction as a product of two numbers, the numerator times the inverse of the denominator. Take a fraction like 3/4. We can write 3/4 as 3 times 1/4, right? And, 1/4 is the inverse of 4. So, it makes sense to invert and multiply. I hope this helps clear any confusion! Please write back if you have any more questions at all. --Sydney, "Dr. Math"
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