Subtract 9/10 from 21/81
21/81 - 9/10 is -173/270.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 10 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 81 × 10 = 810,
21/81 = 21 × 10/81 × 10 = 210/810 - Likewise, for the 2nd fraction, since 10 × 81 = 810,
9/10 = 9 × 81/10 × 81 = 729/810 - Subtract the two like fractions:
210/810 - 729/810 = 210 - 729/810 = -519/810 - After reducing the fraction, the answer is -173/270
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