Subtract 21/42 from 21/80
21/80 - 21/42 is -19/80.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 42 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 80 × 21 = 1680,
21/80 = 21 × 21/80 × 21 = 441/1680 - Likewise, for the 2nd fraction, since 42 × 40 = 1680,
21/42 = 21 × 40/42 × 40 = 840/1680 - Subtract the two like fractions:
441/1680 - 840/1680 = 441 - 840/1680 = -399/1680 - After reducing the fraction, the answer is -19/80
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