Add 20/21 and 21/81
20/21 + 21/81 is 229/189.
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,
20/21 = 20 × 27/21 × 27 = 540/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
21/81 = 21 × 7/81 × 7 = 147/567 - Add the two like fractions:
540/567 + 147/567 = 540 + 147/567 = 687/567 - 687/567 simplified gives 229/189
- So, 20/21 + 21/81 = 229/189
In mixed form: 140/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21+21/81 20/21+42/81 20/42+21/81 60/21+21/81 20/21+63/81 20/63+21/81