Subtract 30/80 from 21/28, Solve 21/28

Subtract 30/80 from 21/28

21/28 - 30/80 is 3/8.

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

Next, find the equivalent fraction of both fractional numbers with denominator 560
For the 1st fraction, since 28 × 20 = 560,
21/28 = 21 × 20/28 × 20 = 420/560
Likewise, for the 2nd fraction, since 80 × 7 = 560,
30/80 = 30 × 7/80 × 7 = 210/560
Subtract the two like fractions:
420/560 - 210/560 = 420 - 210/560 = 210/560
After reducing the fraction, the answer is 3/8

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