Subtract 75/21 from 21/72, Solve 21/72

Subtract 75/21 from 21/72

1^st number: 21/72, 2^nd number: 3 12/21

21/72 - 75/21 is -551/168.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504
Likewise, for the 2nd fraction, since 21 × 24 = 504,
75/21 = 75 × 24/21 × 24 = 1800/504
Subtract the two like fractions:
147/504 - 1800/504 = 147 - 1800/504 = -1653/504
After reducing the fraction, the answer is -551/168

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