Subtract 5/80 from 21/81
21/81 - 5/80 is 85/432.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 80 is 6480
Next, find the equivalent fraction of both fractional numbers with denominator 6480 - For the 1st fraction, since 81 × 80 = 6480,
21/81 = 21 × 80/81 × 80 = 1680/6480 - Likewise, for the 2nd fraction, since 80 × 81 = 6480,
5/80 = 5 × 81/80 × 81 = 405/6480 - Subtract the two like fractions:
1680/6480 - 405/6480 = 1680 - 405/6480 = 1275/6480 - After reducing the fraction, the answer is 85/432
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/81-5/80 21/81-10/80 63/81-5/80 21/81-15/80 21/81-25/80 21/81-35/80