Subtract 21/81 from 4/5
4/5 - 21/81 is 73/135.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 81 is 405
Next, find the equivalent fraction of both fractional numbers with denominator 405 - For the 1st fraction, since 5 × 81 = 405,
4/5 = 4 × 81/5 × 81 = 324/405 - Likewise, for the 2nd fraction, since 81 × 5 = 405,
21/81 = 21 × 5/81 × 5 = 105/405 - Subtract the two like fractions:
324/405 - 105/405 = 324 - 105/405 = 219/405 - After reducing the fraction, the answer is 73/135
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/5-21/81 4/5-42/81 4/10-21/81 12/5-21/81 4/5-63/81 4/15-21/81 20/5-21/81 4/25-21/81 28/5-21/81 4/35-21/81