Subtract 7/21 from 18/20
18/20 - 7/21 is 17/30.
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,
18/20 = 18 × 21/20 × 21 = 378/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
7/21 = 7 × 20/21 × 20 = 140/420 - Subtract the two like fractions:
378/420 - 140/420 = 378 - 140/420 = 238/420 - After reducing the fraction, the answer is 17/30
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