Subtract 56/27 from 21/42, Solve 21/42

Subtract 56/27 from 21/42

1^st number: 21/42, 2^nd number: 2 2/27

21/42 - 56/27 is -85/54.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 27 is 378

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 42 × 9 = 378,
21/42 = 21 × 9/42 × 9 = 189/378
Likewise, for the 2nd fraction, since 27 × 14 = 378,
56/27 = 56 × 14/27 × 14 = 784/378
Subtract the two like fractions:
189/378 - 784/378 = 189 - 784/378 = -595/378
After reducing the fraction, the answer is -85/54

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