Subtract 81/21 from 15/8
1st number: 1 7/8, 2nd number: 3 18/21
15/8 - 81/21 is -111/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
15/8 = 15 × 21/8 × 21 = 315/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
81/21 = 81 × 8/21 × 8 = 648/168 - Subtract the two like fractions:
315/168 - 648/168 = 315 - 648/168 = -333/168 - After reducing the fraction, the answer is -111/56
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