Subtract 21/40 from 7/28
7/28 - 21/40 is -11/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 40 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 28 × 10 = 280,
7/28 = 7 × 10/28 × 10 = 70/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
21/40 = 21 × 7/40 × 7 = 147/280 - Subtract the two like fractions:
70/280 - 147/280 = 70 - 147/280 = -77/280 - After reducing the fraction, the answer is -11/40
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