Subtract 9/21 from 15/20
15/20 - 9/21 is 9/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
9/21 = 9 × 20/21 × 20 = 180/420 - Subtract the two like fractions:
315/420 - 180/420 = 315 - 180/420 = 135/420 - After reducing the fraction, the answer is 9/28
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