Subtract 21/18 from 18/21
1st number: 18/21, 2nd number: 1 3/18
18/21 - 21/18 is -13/42.
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,
18/21 = 18 × 6/21 × 6 = 108/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126 - Subtract the two like fractions:
108/126 - 147/126 = 108 - 147/126 = -39/126 - After reducing the fraction, the answer is -13/42
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