Subtract 8/9 from 21/42
21/42 - 8/9 is -7/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 9 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 42 × 3 = 126,
21/42 = 21 × 3/42 × 3 = 63/126 - Likewise, for the 2nd fraction, since 9 × 14 = 126,
8/9 = 8 × 14/9 × 14 = 112/126 - Subtract the two like fractions:
63/126 - 112/126 = 63 - 112/126 = -49/126 - After reducing the fraction, the answer is -7/18
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