Subtract 3/20 from 3/21
3/21 - 3/20 is -1/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
3/21 = 3 × 20/21 × 20 = 60/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
3/20 = 3 × 21/20 × 21 = 63/420 - Subtract the two like fractions:
60/420 - 63/420 = 60 - 63/420 = -3/420 - After reducing the fraction, the answer is -1/140
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