Subtract 5/42 from 20/80, Solve 20/80

Subtract 5/42 from 20/80

20/80 - 5/42 is 11/84.

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,
20/80 = 20 × 21/80 × 21 = 420/1680
Likewise, for the 2nd fraction, since 42 × 40 = 1680,
5/42 = 5 × 40/42 × 40 = 200/1680
Subtract the two like fractions:
420/1680 - 200/1680 = 420 - 200/1680 = 220/1680
After reducing the fraction, the answer is 11/84

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