Subtract 28/21 from 7/20, Solve 7/20

Subtract 28/21 from 7/20

1^st number: 7/20, 2^nd number: 1 7/21

7/20 - 28/21 is -59/60.

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,
7/20 = 7 × 21/20 × 21 = 147/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
28/21 = 28 × 20/21 × 20 = 560/420
Subtract the two like fractions:
147/420 - 560/420 = 147 - 560/420 = -413/420
After reducing the fraction, the answer is -59/60

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