Subtract 42/70 from 20/81
20/81 - 42/70 is -143/405.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 70 is 5670
Next, find the equivalent fraction of both fractional numbers with denominator 5670 - For the 1st fraction, since 81 × 70 = 5670,
20/81 = 20 × 70/81 × 70 = 1400/5670 - Likewise, for the 2nd fraction, since 70 × 81 = 5670,
42/70 = 42 × 81/70 × 81 = 3402/5670 - Subtract the two like fractions:
1400/5670 - 3402/5670 = 1400 - 3402/5670 = -2002/5670 - After reducing the fraction, the answer is -143/405
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