Subtract 40/81 from 21/42
21/42 - 40/81 is 1/162.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 81 is 1134
Next, find the equivalent fraction of both fractional numbers with denominator 1134 - For the 1st fraction, since 42 × 27 = 1134,
21/42 = 21 × 27/42 × 27 = 567/1134 - Likewise, for the 2nd fraction, since 81 × 14 = 1134,
40/81 = 40 × 14/81 × 14 = 560/1134 - Subtract the two like fractions:
567/1134 - 560/1134 = 567 - 560/1134 = 7/1134 - After reducing the fraction, the answer is 1/162
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