Subtract 1/42 from 21/27, Solve 21/27

Subtract 1/42 from 21/27

21/27 - 1/42 is 95/126.

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

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 27 × 14 = 378,
21/27 = 21 × 14/27 × 14 = 294/378
Likewise, for the 2nd fraction, since 42 × 9 = 378,
1/42 = 1 × 9/42 × 9 = 9/378
Subtract the two like fractions:
294/378 - 9/378 = 294 - 9/378 = 285/378
After reducing the fraction, the answer is 95/126

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