Subtract 21/27 from 80/42, Solve 1 38/42

Subtract 21/27 from 80/42

1^st number: 1 38/42, 2^nd number: 21/27

80/42 - 21/27 is 71/63.

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,
80/42 = 80 × 9/42 × 9 = 720/378
Likewise, for the 2nd fraction, since 27 × 14 = 378,
21/27 = 21 × 14/27 × 14 = 294/378
Subtract the two like fractions:
720/378 - 294/378 = 720 - 294/378 = 426/378
After reducing the fraction, the answer is 71/63
In mixed form: 18/63

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