Subtract 63/21 from 5/20, Solve 5/20

Subtract 63/21 from 5/20

1^st number: 5/20, 2^nd number: 3 0/21

5/20 - 63/21 is -11/4.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 20 × 21 = 420,
5/20 = 5 × 21/20 × 21 = 105/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
63/21 = 63 × 20/21 × 20 = 1260/420
Subtract the two like fractions:
105/420 - 1260/420 = 105 - 1260/420 = -1155/420
After reducing the fraction, the answer is -11/4

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