Subtract 21/28 from 15/80, Solve 15/80

Subtract 21/28 from 15/80

15/80 - 21/28 is -9/16.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 28 is 560

Next, find the equivalent fraction of both fractional numbers with denominator 560
For the 1st fraction, since 80 × 7 = 560,
15/80 = 15 × 7/80 × 7 = 105/560
Likewise, for the 2nd fraction, since 28 × 20 = 560,
21/28 = 21 × 20/28 × 20 = 420/560
Subtract the two like fractions:
105/560 - 420/560 = 105 - 420/560 = -315/560
After reducing the fraction, the answer is -9/16

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