Subtract 21/27 from 18/40, Solve 18/40

Subtract 21/27 from 18/40

18/40 - 21/27 is -59/180.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 27 is 1080

Next, find the equivalent fraction of both fractional numbers with denominator 1080
For the 1st fraction, since 40 × 27 = 1080,
18/40 = 18 × 27/40 × 27 = 486/1080
Likewise, for the 2nd fraction, since 27 × 40 = 1080,
21/27 = 21 × 40/27 × 40 = 840/1080
Subtract the two like fractions:
486/1080 - 840/1080 = 486 - 840/1080 = -354/1080
After reducing the fraction, the answer is -59/180

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