Subtract 20/21 from 15/28
15/28 - 20/21 is -5/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
15/28 = 15 × 3/28 × 3 = 45/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Subtract the two like fractions:
45/84 - 80/84 = 45 - 80/84 = -35/84 - After reducing the fraction, the answer is -5/12
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