Subtract 5/8 from 18/42
18/42 - 5/8 is -11/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 42 × 4 = 168,
18/42 = 18 × 4/42 × 4 = 72/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
5/8 = 5 × 21/8 × 21 = 105/168 - Subtract the two like fractions:
72/168 - 105/168 = 72 - 105/168 = -33/168 - After reducing the fraction, the answer is -11/56
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