Subtract 9/7 from 21/54, Solve 21/54

Subtract 9/7 from 21/54

1^st number: 21/54, 2^nd number: 1 2/7

21/54 - 9/7 is -113/126.

Find the least common denominator or LCM of the two denominators:
LCM of 54 and 7 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 7 × 54 = 378,
9/7 = 9 × 54/7 × 54 = 486/378
Subtract the two like fractions:
147/378 - 486/378 = 147 - 486/378 = -339/378
After reducing the fraction, the answer is -113/126

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