Subtract 81/42 from 28/20
1st number: 1 8/20, 2nd number: 1 39/42
28/20 - 81/42 is -37/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 42 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
28/20 = 28 × 21/20 × 21 = 588/420 - Likewise, for the 2nd fraction, since 42 × 10 = 420,
81/42 = 81 × 10/42 × 10 = 810/420 - Subtract the two like fractions:
588/420 - 810/420 = 588 - 810/420 = -222/420 - After reducing the fraction, the answer is -37/70
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