Subtract 7/8 from 21/63, Solve 21/63

Subtract 7/8 from 21/63

21/63 - 7/8 is -13/24.

Find the least common denominator or LCM of the two denominators:
LCM of 63 and 8 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 63 × 8 = 504,
21/63 = 21 × 8/63 × 8 = 168/504
Likewise, for the 2nd fraction, since 8 × 63 = 504,
7/8 = 7 × 63/8 × 63 = 441/504
Subtract the two like fractions:
168/504 - 441/504 = 168 - 441/504 = -273/504
After reducing the fraction, the answer is -13/24

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