Subtract 21/81 from 27/40, Solve 27/40

Subtract 21/81 from 27/40

27/40 - 21/81 is 449/1080.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 81 is 3240

Next, find the equivalent fraction of both fractional numbers with denominator 3240
For the 1st fraction, since 40 × 81 = 3240,
27/40 = 27 × 81/40 × 81 = 2187/3240
Likewise, for the 2nd fraction, since 81 × 40 = 3240,
21/81 = 21 × 40/81 × 40 = 840/3240
Subtract the two like fractions:
2187/3240 - 840/3240 = 2187 - 840/3240 = 1347/3240
After reducing the fraction, the answer is 449/1080

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