Subtract 12/18 from 8/21
8/21 - 12/18 is -2/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
8/21 = 8 × 6/21 × 6 = 48/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
12/18 = 12 × 7/18 × 7 = 84/126 - Subtract the two like fractions:
48/126 - 84/126 = 48 - 84/126 = -36/126 - After reducing the fraction, the answer is -2/7
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