Subtract 60/42 from 15/80, Solve 15/80

Subtract 60/42 from 15/80

1^st number: 15/80, 2^nd number: 1 18/42

15/80 - 60/42 is -139/112.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 42 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 80 × 21 = 1680,
15/80 = 15 × 21/80 × 21 = 315/1680
Likewise, for the 2nd fraction, since 42 × 40 = 1680,
60/42 = 60 × 40/42 × 40 = 2400/1680
Subtract the two like fractions:
315/1680 - 2400/1680 = 315 - 2400/1680 = -2085/1680
After reducing the fraction, the answer is -139/112

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