Subtract 18/28 from 7/21
7/21 - 18/28 is -13/42.
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,
7/21 = 7 × 4/21 × 4 = 28/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
18/28 = 18 × 3/28 × 3 = 54/84 - Subtract the two like fractions:
28/84 - 54/84 = 28 - 54/84 = -26/84 - After reducing the fraction, the answer is -13/42
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