Subtract 90/72 from 10/42, Solve 10/42

Subtract 90/72 from 10/42

1^st number: 10/42, 2^nd number: 1 18/72

10/42 - 90/72 is -85/84.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 42 × 12 = 504,
10/42 = 10 × 12/42 × 12 = 120/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
90/72 = 90 × 7/72 × 7 = 630/504
Subtract the two like fractions:
120/504 - 630/504 = 120 - 630/504 = -510/504
After reducing the fraction, the answer is -85/84

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