Subtract 63/12 from 21/40, Solve 21/40

Subtract 63/12 from 21/40

1^st number: 21/40, 2^nd number: 5 3/12

21/40 - 63/12 is -189/40.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 12 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 40 × 3 = 120,
21/40 = 21 × 3/40 × 3 = 63/120
Likewise, for the 2nd fraction, since 12 × 10 = 120,
63/12 = 63 × 10/12 × 10 = 630/120
Subtract the two like fractions:
63/120 - 630/120 = 63 - 630/120 = -567/120
After reducing the fraction, the answer is -189/40

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