Subtract 21/81 from 15/70
15/70 - 21/81 is -17/378.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 81 is 5670
Next, find the equivalent fraction of both fractional numbers with denominator 5670 - For the 1st fraction, since 70 × 81 = 5670,
15/70 = 15 × 81/70 × 81 = 1215/5670 - Likewise, for the 2nd fraction, since 81 × 70 = 5670,
21/81 = 21 × 70/81 × 70 = 1470/5670 - Subtract the two like fractions:
1215/5670 - 1470/5670 = 1215 - 1470/5670 = -255/5670 - After reducing the fraction, the answer is -17/378
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