Subtract 27/36 from 15/21, Solve 15/21

Subtract 27/36 from 15/21

15/21 - 27/36 is -1/28.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 36 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 21 × 12 = 252,
15/21 = 15 × 12/21 × 12 = 180/252
Likewise, for the 2nd fraction, since 36 × 7 = 252,
27/36 = 27 × 7/36 × 7 = 189/252
Subtract the two like fractions:
180/252 - 189/252 = 180 - 189/252 = -9/252
After reducing the fraction, the answer is -1/28

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