Subtract 30/72 from 72/21, Solve 3 9/21

Subtract 30/72 from 72/21

1^st number: 3 9/21, 2^nd number: 30/72

72/21 - 30/72 is 253/84.

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

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 21 × 24 = 504,
72/21 = 72 × 24/21 × 24 = 1728/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
30/72 = 30 × 7/72 × 7 = 210/504
Subtract the two like fractions:
1728/504 - 210/504 = 1728 - 210/504 = 1518/504
After reducing the fraction, the answer is 253/84
In mixed form: 31/84

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