Subtract 90/54 from 81/42, Solve 1 39/42

Subtract 90/54 from 81/42

1^st number: 1 39/42, 2^nd number: 1 36/54

81/42 - 90/54 is 11/42.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 54 is 378

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 42 × 9 = 378,
81/42 = 81 × 9/42 × 9 = 729/378
Likewise, for the 2nd fraction, since 54 × 7 = 378,
90/54 = 90 × 7/54 × 7 = 630/378
Subtract the two like fractions:
729/378 - 630/378 = 729 - 630/378 = 99/378
After reducing the fraction, the answer is 11/42

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