Subtract 8/14 from 21/54, Solve 21/54

Subtract 8/14 from 21/54

21/54 - 8/14 is -23/126.

Find the least common denominator or LCM of the two denominators:
LCM of 54 and 14 is 378

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 54 × 7 = 378,
21/54 = 21 × 7/54 × 7 = 147/378
Likewise, for the 2nd fraction, since 14 × 27 = 378,
8/14 = 8 × 27/14 × 27 = 216/378
Subtract the two like fractions:
147/378 - 216/378 = 147 - 216/378 = -69/378
After reducing the fraction, the answer is -23/126

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