Subtract 81/90 from 7/20
7/20 - 81/90 is -11/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 90 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 20 × 9 = 180,
7/20 = 7 × 9/20 × 9 = 63/180 - Likewise, for the 2nd fraction, since 90 × 2 = 180,
81/90 = 81 × 2/90 × 2 = 162/180 - Subtract the two like fractions:
63/180 - 162/180 = 63 - 162/180 = -99/180 - After reducing the fraction, the answer is -11/20
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