Subtract 42/21 from 3/36, Solve 3/36

Subtract 42/21 from 3/36

1^st number: 3/36, 2^nd number: 2 0/21

3/36 - 42/21 is -23/12.

Find the least common denominator or LCM of the two denominators:
LCM of 36 and 21 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 36 × 7 = 252,
3/36 = 3 × 7/36 × 7 = 21/252
Likewise, for the 2nd fraction, since 21 × 12 = 252,
42/21 = 42 × 12/21 × 12 = 504/252
Subtract the two like fractions:
21/252 - 504/252 = 21 - 504/252 = -483/252
After reducing the fraction, the answer is -23/12

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