Subtract 18/21 from 27/56, Solve 27/56

Subtract 18/21 from 27/56

27/56 - 18/21 is -3/8.

Find the least common denominator or LCM of the two denominators:
LCM of 56 and 21 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 56 × 3 = 168,
27/56 = 27 × 3/56 × 3 = 81/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
18/21 = 18 × 8/21 × 8 = 144/168
Subtract the two like fractions:
81/168 - 144/168 = 81 - 144/168 = -63/168
After reducing the fraction, the answer is -3/8

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