Subtract 36/81 from 72/21, Solve 3 9/21

Subtract 36/81 from 72/21

1^st number: 3 9/21, 2^nd number: 36/81

72/21 - 36/81 is 188/63.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 81 is 567

Next, find the equivalent fraction of both fractional numbers with denominator 567
For the 1st fraction, since 21 × 27 = 567,
72/21 = 72 × 27/21 × 27 = 1944/567
Likewise, for the 2nd fraction, since 81 × 7 = 567,
36/81 = 36 × 7/81 × 7 = 252/567
Subtract the two like fractions:
1944/567 - 252/567 = 1944 - 252/567 = 1692/567
After reducing the fraction, the answer is 188/63
In mixed form: 262/63

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