Subtract 63/20 from 15/42, Solve 15/42

Subtract 63/20 from 15/42

1^st number: 15/42, 2^nd number: 3 3/20

15/42 - 63/20 is -391/140.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 42 × 10 = 420,
15/42 = 15 × 10/42 × 10 = 150/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
63/20 = 63 × 21/20 × 21 = 1323/420
Subtract the two like fractions:
150/420 - 1323/420 = 150 - 1323/420 = -1173/420
After reducing the fraction, the answer is -391/140

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