Add 5/21 and 15/81
5/21 + 15/81 is 80/189.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 81 is 567
Next, find the equivalent fraction of both fractional numbers with denominator 567 - For the 1st fraction, since 21 × 27 = 567,
5/21 = 5 × 27/21 × 27 = 135/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
15/81 = 15 × 7/81 × 7 = 105/567 - Add the two like fractions:
135/567 + 105/567 = 135 + 105/567 = 240/567 - 240/567 simplified gives 80/189
- So, 5/21 + 15/81 = 80/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21+15/81 5/21+30/81 5/42+15/81 15/21+15/81 5/21+45/81 5/63+15/81 25/21+15/81 5/21+75/81 35/21+15/81