Add 21/81 and 75/80
21/81 + 75/80 is 517/432.
Steps for adding 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,
75/80 = 75 × 81/80 × 81 = 6075/6480 - Add the two like fractions:
1680/6480 + 6075/6480 = 1680 + 6075/6480 = 7755/6480 - 7755/6480 simplified gives 517/432
- So, 21/81 + 75/80 = 517/432
In mixed form: 185/432
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/81+75/80 63/81+75/80