Subtract 21/81 from 1/18
1/18 - 21/81 is -11/54.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 81 is 162
Next, find the equivalent fraction of both fractional numbers with denominator 162 - For the 1st fraction, since 18 × 9 = 162,
1/18 = 1 × 9/18 × 9 = 9/162 - Likewise, for the 2nd fraction, since 81 × 2 = 162,
21/81 = 21 × 2/81 × 2 = 42/162 - Subtract the two like fractions:
9/162 - 42/162 = 9 - 42/162 = -33/162 - After reducing the fraction, the answer is -11/54
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/18-21/81 1/18-42/81 1/36-21/81 3/18-21/81 1/18-63/81 1/54-21/81 5/18-21/81 1/90-21/81 7/18-21/81