Subtract 28/84 from 3/21
3/21 - 28/84 is -4/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
3/21 = 3 × 4/21 × 4 = 12/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
28/84 = 28 × 1/84 × 1 = 28/84 - Subtract the two like fractions:
12/84 - 28/84 = 12 - 28/84 = -16/84 - After reducing the fraction, the answer is -4/21
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