Subtract 21/42 from 10/72, Solve 10/72

Subtract 21/42 from 10/72

10/72 - 21/42 is -13/36.

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

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
10/72 = 10 × 7/72 × 7 = 70/504
Likewise, for the 2nd fraction, since 42 × 12 = 504,
21/42 = 21 × 12/42 × 12 = 252/504
Subtract the two like fractions:
70/504 - 252/504 = 70 - 252/504 = -182/504
After reducing the fraction, the answer is -13/36

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