MATH
posted by cha on .
Subtract six and onehalf minus four and seventenths. Justify your steps

6 1/2  4 7/10
You'll need to change the first fraction so that it has the same denominator. You'll also need to regroup.
6 1/2 = 5 15/10
5 15/10  4 7/10 = ? 
6 1/2  4 7/10
first, we convert this to improper fraction (numerator is greater than denominator). We do this be multiplying the whole number to the denominator then add to the numerator:
(6*2 + 1)/2  (4*10 + 7)/10
(12 + 1)/2  (40 + 7)/10
13/2  47/10
Then, we find the least common denominator (LCD) of the fractions. Their LCD is 10 (it is the smallest number where we can divide 2 and 10 without remainder). We have no problem for the second fraction (since its denominator is already 10). For the first fraction, we do this by dividing the LCD by 2 (10/2 = 5) then multiply this to numerator. Thus,
13*5 / 10  47/10
65/10  47/10
(6547)/10
18/10 or 9/5 or 1 4/5
hope this helps~ :) 
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