Subtract 21/18 from 18/42
1st number: 18/42, 2nd number: 1 3/18
18/42 - 21/18 is -31/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 42 × 3 = 126,
18/42 = 18 × 3/42 × 3 = 54/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126 - Subtract the two like fractions:
54/126 - 147/126 = 54 - 147/126 = -93/126 - After reducing the fraction, the answer is -31/42
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