Subtract 21/8 from 42/84
1st number: 42/84, 2nd number: 2 5/8
42/84 - 21/8 is -17/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 84 × 2 = 168,
42/84 = 42 × 2/84 × 2 = 84/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
21/8 = 21 × 21/8 × 21 = 441/168 - Subtract the two like fractions:
84/168 - 441/168 = 84 - 441/168 = -357/168 - After reducing the fraction, the answer is -17/8
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