Subtract 20/21 from 7/12
7/12 - 20/21 is -31/84.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
7/12 = 7 × 7/12 × 7 = 49/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Subtract the two like fractions:
49/84 - 80/84 = 49 - 80/84 = -31/84
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