Subtract 9/20 from 21/42
21/42 - 9/20 is 1/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 42 × 10 = 420,
21/42 = 21 × 10/42 × 10 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
9/20 = 9 × 21/20 × 21 = 189/420 - Subtract the two like fractions:
210/420 - 189/420 = 210 - 189/420 = 21/420 - After reducing the fraction, the answer is 1/20
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