Subtract 3/21 from 81/42, Solve 1 39/42

Subtract 3/21 from 81/42

1^st number: 1 39/42, 2^nd number: 3/21

81/42 - 3/21 is 25/14.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42

Next, find the equivalent fraction of both fractional numbers with denominator 42
For the 1st fraction, since 42 × 1 = 42,
81/42 = 81 × 1/42 × 1 = 81/42
Likewise, for the 2nd fraction, since 21 × 2 = 42,
3/21 = 3 × 2/21 × 2 = 6/42
Subtract the two like fractions:
81/42 - 6/42 = 81 - 6/42 = 75/42
After reducing the fraction, the answer is 25/14
In mixed form: 111/14

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