Adding FractionsDate: 7/26/96 at 21:40:8 From: Anonymous Subject: Adding Fractions How do you add fractions? Date: 7/26/96 at 23:30:53 From: Doctor Paul Subject: Re: Adding Fractions There are two cases: Case One: You have the same denominator (the number on bottom) for both fractions. Example: 3 1 - + - = ? 7 7 To do a problem where the bottom number is the same, just add the top numbers and put that total over the common denominator. So, 3 1 4 - + - = - 7 7 7 Case Two: To add fractions where the bottom numbers are different, we first put the fractions over a common denominator and then add using the previous method. Example: 2 1 - + - = ? 7 2 We have to put each term over the same denominator. Note that if I multiply that top *AND* the bottom of a fraction by a number the fraction's value doesn't change. I will multiply the 2/7 term by some number (a/a). How do I choose 'a'? I choose a to be the other denominator. I do the same to the 1/2 term: multiply it by (7/7) so we get: 2 * (2) 1 * (7) ------- + ------- 7 * (2) 2 * (7) 4 7 11 ---- + ---- = ---- 14 14 14 I hope this helps. -Doctor Paul, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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