Subtract 7/15 from 5/21
5/21 - 7/15 is -8/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
5/21 = 5 × 5/21 × 5 = 25/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
7/15 = 7 × 7/15 × 7 = 49/105 - Subtract the two like fractions:
25/105 - 49/105 = 25 - 49/105 = -24/105 - After reducing the fraction, the answer is -8/35
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