Subtract 40/80 from 5/21
5/21 - 40/80 is -11/42.
Steps for subtracting fractions
- 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,
5/21 = 5 × 80/21 × 80 = 400/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
40/80 = 40 × 21/80 × 21 = 840/1680 - Subtract the two like fractions:
400/1680 - 840/1680 = 400 - 840/1680 = -440/1680 - After reducing the fraction, the answer is -11/42
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