Subtract 4/40 from 21/28
21/28 - 4/40 is 13/20.
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,
21/28 = 21 × 10/28 × 10 = 210/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
4/40 = 4 × 7/40 × 7 = 28/280 - Subtract the two like fractions:
210/280 - 28/280 = 210 - 28/280 = 182/280 - After reducing the fraction, the answer is 13/20
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