Subtract 18/15 from 20/21
1st number: 20/21, 2nd number: 1 3/15
20/21 - 18/15 is -26/105.
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,
20/21 = 20 × 5/21 × 5 = 100/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
18/15 = 18 × 7/15 × 7 = 126/105 - Subtract the two like fractions:
100/105 - 126/105 = 100 - 126/105 = -26/105
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