Subtract 80/81 from 7/20
7/20 - 80/81 is -1033/1620.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 81 is 1620
Next, find the equivalent fraction of both fractional numbers with denominator 1620 - For the 1st fraction, since 20 × 81 = 1620,
7/20 = 7 × 81/20 × 81 = 567/1620 - Likewise, for the 2nd fraction, since 81 × 20 = 1620,
80/81 = 80 × 20/81 × 20 = 1600/1620 - Subtract the two like fractions:
567/1620 - 1600/1620 = 567 - 1600/1620 = -1033/1620
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