Subtract 8/20 from 5/21
5/21 - 8/20 is -17/105.
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,
5/21 = 5 × 20/21 × 20 = 100/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
8/20 = 8 × 21/20 × 21 = 168/420 - Subtract the two like fractions:
100/420 - 168/420 = 100 - 168/420 = -68/420 - After reducing the fraction, the answer is -17/105
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