Subtract 21/81 from 42/12, Solve 3 6/12

Subtract 21/81 from 42/12

1^st number: 3 6/12, 2^nd number: 21/81

42/12 - 21/81 is 175/54.

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,
42/12 = 42 × 27/12 × 27 = 1134/324
Likewise, for the 2nd fraction, since 81 × 4 = 324,
21/81 = 21 × 4/81 × 4 = 84/324
Subtract the two like fractions:
1134/324 - 84/324 = 1134 - 84/324 = 1050/324
After reducing the fraction, the answer is 175/54
In mixed form: 313/54

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