Subtract 80/81 from 21/4
1st number: 5 1/4, 2nd number: 80/81
21/4 - 80/81 is 1381/324.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 4 and 81 is 324
Next, find the equivalent fraction of both fractional numbers with denominator 324 - For the 1st fraction, since 4 × 81 = 324,
21/4 = 21 × 81/4 × 81 = 1701/324 - Likewise, for the 2nd fraction, since 81 × 4 = 324,
80/81 = 80 × 4/81 × 4 = 320/324 - Subtract the two like fractions:
1701/324 - 320/324 = 1701 - 320/324 = 1381/324 - In mixed form: 485/324
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/4-80/81 21/8-80/81 63/4-80/81 21/12-80/81 21/20-80/81 21/28-80/81