Subtract 15/42 from 10/80, Solve 10/80

Subtract 15/42 from 10/80

10/80 - 15/42 is -13/56.

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,
10/80 = 10 × 21/80 × 21 = 210/1680
Likewise, for the 2nd fraction, since 42 × 40 = 1680,
15/42 = 15 × 40/42 × 40 = 600/1680
Subtract the two like fractions:
210/1680 - 600/1680 = 210 - 600/1680 = -390/1680
After reducing the fraction, the answer is -13/56

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