Subtract 21/10 from 72/81
1st number: 72/81, 2nd number: 2 1/10
72/81 - 21/10 is -109/90.
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,
72/81 = 72 × 10/81 × 10 = 720/810 - Likewise, for the 2nd fraction, since 10 × 81 = 810,
21/10 = 21 × 81/10 × 81 = 1701/810 - Subtract the two like fractions:
720/810 - 1701/810 = 720 - 1701/810 = -981/810 - After reducing the fraction, the answer is -109/90
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