Subtract 20/12 from 21/56, Solve 21/56

Subtract 20/12 from 21/56

1^st number: 21/56, 2^nd number: 1 8/12

21/56 - 20/12 is -31/24.

Find the least common denominator or LCM of the two denominators:
LCM of 56 and 12 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 56 × 3 = 168,
21/56 = 21 × 3/56 × 3 = 63/168
Likewise, for the 2nd fraction, since 12 × 14 = 168,
20/12 = 20 × 14/12 × 14 = 280/168
Subtract the two like fractions:
63/168 - 280/168 = 63 - 280/168 = -217/168
After reducing the fraction, the answer is -31/24

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