Subtract 18/81 from 4/42
4/42 - 18/81 is -8/63.
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,
4/42 = 4 × 27/42 × 27 = 108/1134 - Likewise, for the 2nd fraction, since 81 × 14 = 1134,
18/81 = 18 × 14/81 × 14 = 252/1134 - Subtract the two like fractions:
108/1134 - 252/1134 = 108 - 252/1134 = -144/1134 - After reducing the fraction, the answer is -8/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/42-18/81 4/42-36/81 4/84-18/81 12/42-18/81 4/42-54/81 20/42-18/81 4/42-90/81 28/42-18/81