Subtract 7/8 from 21/42
2142 - 78 is -38.
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,
2142 = 21 × 442 × 4 = 84168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
78 = 7 × 218 × 21 = 147168 - Subtract the two like fractions:
84168 - 147168 = 84 - 147168 = -63168 - After reducing the fraction, the answer is -38
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