Subtract 21/40 from 3/8
3/8 - 21/40 is -3/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 40 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 8 × 5 = 40,
3/8 = 3 × 5/8 × 5 = 15/40 - Likewise, for the 2nd fraction, since 40 × 1 = 40,
21/40 = 21 × 1/40 × 1 = 21/40 - Subtract the two like fractions:
15/40 - 21/40 = 15 - 21/40 = -6/40 - After reducing the fraction, the answer is -3/20
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