Subtract 72/18 from 81/21
1st number: 3 18/21, 2nd number: 4 0/18
81/21 - 72/18 is -1/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
81/21 = 81 × 6/21 × 6 = 486/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
72/18 = 72 × 7/18 × 7 = 504/126 - Subtract the two like fractions:
486/126 - 504/126 = 486 - 504/126 = -18/126 - After reducing the fraction, the answer is -1/7
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