Dividing FractionsDate: 7/5/96 at 14:31:15 From: kcl Subject: Dividing Fractions Dr.Math Hi! I'm in grade 6 going on to grade 7 next year. I always get stuck on dividing fractions. Please help me! Karen Date: 7/5/96 at 16:48:4 From: Doctor Anthony Subject: Re: Dividing Fractions A simple rule to remember when dividing fractions is that you take the fraction on the bottom line (denominator), turn it upside down and multiply. So 5/(1/2) is the same as 5*(2/1) = 10 You will notice that the (1/2) on the bottom line has been turned upside down to 2/1, or simply 2, and then multiplied. The reason why this method works is that multiplying both top line and bottom line by the bottom line turned upside down causes the bottom line to become 1, and we need only then consider what happens on the top line. Example Simplify 5/8 (5/8)(4/3) 5/6 --- = ---------- = ----- = 5/6 3/4 (3/4)(4/3) 1 In practice we don't need to carry out all the steps shown above. We just do the 'invert and multiply' that I described at the start. 5/8 --- = 5/8 * 4/3 = 5/6 3/4 -Doctor Anthony, The Math Forum Check out our web site! http://mathforum.org/dr.math/ Date: 7/5/96 at 17:36:30 From: kcl Subject: More on Dividing Fractions Dr.Math, Hi, again! I still don't understand what you meant. Please send me more details about dividing fractions. Karen Date: 7/19/96 at 17:10:31 From: Doctor Robert Subject: Re: More on Dividing Fractions If you know how to multiply fractions, dividing is pretty easy. You multiply fractions by multiplying the numerators together to get the numerator of the answer, and multiplying the denominators together to get the denominator of the answer. For example 2/3 times 4/5 = 8/15. To divide one fraction by another, you simply invert the divisor (invert means make the numerator the denominator and make the denominator the numerator) and multiply. For example 2/3 divided by 4/5 is the same as 2/3 times 5/4 which is 10/12 or 5/6 when reduced. Good luck. -Doctor Robert, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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