Subtract 80/81 from 81/90
81/90 - 80/81 is -71/810.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 81 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 90 × 9 = 810,
81/90 = 81 × 9/90 × 9 = 729/810 - Likewise, for the 2nd fraction, since 81 × 10 = 810,
80/81 = 80 × 10/81 × 10 = 800/810 - Subtract the two like fractions:
729/810 - 800/810 = 729 - 800/810 = -71/810
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