To subtract fractions you put the two fractions one over the other. If you have two mixed numbers you subtract the fraction part first then the whole number. If the two fractions have different denomenators you have to find the LCD (SEE VOCAB POST), of each fraction then subtract them. If the fraction on the bottom is bigger than the fraction on the top you have to borrow, by taking one whole from the whole number part of the mixed number. That whole number is the same two numbers as the numerator and the denominator. (the denominator is the same as the fraction part of the mixed number). You add that whole fraction to the current fraction to get the number that you can subtract. You then do the problem, and get your answer. You can also go into negatives, if the top fraction is greater than the lower. All you have to do is subtract the two fractions and get your negative number, then you subtract your two whole numbers. You take the negative number and subtract it from the answer you got from subtracting the two whole numbers and you get your answer.
Ex.: 4 3/7 - 3 6/7 if you borrow you take 1 (7/7) from the 4 and add it to 3/7 now your question is 3 10/7 - 3 6/7 you do 10/7 - 6/7 and get 4/7 then 3 - 3 which is 0 so your answer is 4/7
Ex.: 4 3/7 - 3 6/7 if you go into negatives you have to do 3/7 - 6/7 which is -3/7 then 4 - 3 is 1 so you subtract 3/7 from 1 (7/7) and get 4/7
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