Subtract 21/48 from 18/42
18/42 - 21/48 is -1/112.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 48 is 336
Next, find the equivalent fraction of both fractional numbers with denominator 336 - For the 1st fraction, since 42 × 8 = 336,
18/42 = 18 × 8/42 × 8 = 144/336 - Likewise, for the 2nd fraction, since 48 × 7 = 336,
21/48 = 21 × 7/48 × 7 = 147/336 - Subtract the two like fractions:
144/336 - 147/336 = 144 - 147/336 = -3/336 - After reducing the fraction, the answer is -1/112
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