Subtract 5/80 from 18/21, Solve 18/21

Subtract 5/80 from 18/21

18/21 - 5/80 is 89/112.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 21 × 80 = 1680,
18/21 = 18 × 80/21 × 80 = 1440/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
5/80 = 5 × 21/80 × 21 = 105/1680
Subtract the two like fractions:
1440/1680 - 105/1680 = 1440 - 105/1680 = 1335/1680
After reducing the fraction, the answer is 89/112

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