Subtract 15/21 from 3/12
3/12 - 15/21 is -13/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
3/12 = 3 × 7/12 × 7 = 21/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
15/21 = 15 × 4/21 × 4 = 60/84 - Subtract the two like fractions:
21/84 - 60/84 = 21 - 60/84 = -39/84 - After reducing the fraction, the answer is -13/28
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