Subtract 42/81 from 21/70
21/70 - 42/81 is -59/270.
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,
21/70 = 21 × 81/70 × 81 = 1701/5670 - Likewise, for the 2nd fraction, since 81 × 70 = 5670,
42/81 = 42 × 70/81 × 70 = 2940/5670 - Subtract the two like fractions:
1701/5670 - 2940/5670 = 1701 - 2940/5670 = -1239/5670 - After reducing the fraction, the answer is -59/270
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