Subtract 12/8 from 1/21, Solve 1/21

Subtract 12/8 from 1/21

1^st number: 1/21, 2^nd number: 1 4/8

1/21 - 12/8 is -61/42.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 21 × 8 = 168,
1/21 = 1 × 8/21 × 8 = 8/168
Likewise, for the 2nd fraction, since 8 × 21 = 168,
12/8 = 12 × 21/8 × 21 = 252/168
Subtract the two like fractions:
8/168 - 252/168 = 8 - 252/168 = -244/168
After reducing the fraction, the answer is -61/42

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