Subtract 8/12 from 81/21, Solve 3 18/21

Subtract 8/12 from 81/21

1^st number: 3 18/21, 2^nd number: 8/12

81/21 - 8/12 is 67/21.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 12 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 21 × 4 = 84,
81/21 = 81 × 4/21 × 4 = 324/84
Likewise, for the 2nd fraction, since 12 × 7 = 84,
8/12 = 8 × 7/12 × 7 = 56/84
Subtract the two like fractions:
324/84 - 56/84 = 324 - 56/84 = 268/84
After reducing the fraction, the answer is 67/21
In mixed form: 34/21

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