Subtract 45/42 from 8/20, Solve 8/20

Subtract 45/42 from 8/20

1^st number: 8/20, 2^nd number: 1 3/42

8/20 - 45/42 is -47/70.

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

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 20 × 21 = 420,
8/20 = 8 × 21/20 × 21 = 168/420
Likewise, for the 2nd fraction, since 42 × 10 = 420,
45/42 = 45 × 10/42 × 10 = 450/420
Subtract the two like fractions:
168/420 - 450/420 = 168 - 450/420 = -282/420
After reducing the fraction, the answer is -47/70

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