Subtract 7/30 from 18/81
18/81 - 7/30 is -1/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 30 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 81 × 10 = 810,
18/81 = 18 × 10/81 × 10 = 180/810 - Likewise, for the 2nd fraction, since 30 × 27 = 810,
7/30 = 7 × 27/30 × 27 = 189/810 - Subtract the two like fractions:
180/810 - 189/810 = 180 - 189/810 = -9/810 - After reducing the fraction, the answer is -1/90
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