Subtract 20/21 from 5/40, Solve 5/40

Subtract 20/21 from 5/40

5/40 - 20/21 is -139/168.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 40 × 21 = 840,
5/40 = 5 × 21/40 × 21 = 105/840
Likewise, for the 2nd fraction, since 21 × 40 = 840,
20/21 = 20 × 40/21 × 40 = 800/840
Subtract the two like fractions:
105/840 - 800/840 = 105 - 800/840 = -695/840
After reducing the fraction, the answer is -139/168

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