Subtract 21/18 from 20/21
1st number: 20/21, 2nd number: 1 3/18
20/21 - 21/18 is -3/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
20/21 = 20 × 6/21 × 6 = 120/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126 - Subtract the two like fractions:
120/126 - 147/126 = 120 - 147/126 = -27/126 - After reducing the fraction, the answer is -3/14
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