Subtract 21/81 from 45/12, Solve 3 9/12

Subtract 21/81 from 45/12

1^st number: 3 9/12, 2^nd number: 21/81

45/12 - 21/81 is 377/108.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 81 is 324

Next, find the equivalent fraction of both fractional numbers with denominator 324
For the 1st fraction, since 12 × 27 = 324,
45/12 = 45 × 27/12 × 27 = 1215/324
Likewise, for the 2nd fraction, since 81 × 4 = 324,
21/81 = 21 × 4/81 × 4 = 84/324
Subtract the two like fractions:
1215/324 - 84/324 = 1215 - 84/324 = 1131/324
After reducing the fraction, the answer is 377/108
In mixed form: 353/108

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