Subtract 21/28 from 12/21
12/21 - 21/28 is -5/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 28 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
12/21 = 12 × 4/21 × 4 = 48/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
21/28 = 21 × 3/28 × 3 = 63/84 - Subtract the two like fractions:
48/84 - 63/84 = 48 - 63/84 = -15/84 - After reducing the fraction, the answer is -5/28
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