Add 20/42 and 90/81
1st number: 20/42, 2nd number: 1 9/81
20/42 + 90/81 is 100/63.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 81 is 1134
Next, find the equivalent fraction of both fractional numbers with denominator 1134 - For the 1st fraction, since 42 × 27 = 1134,
20/42 = 20 × 27/42 × 27 = 540/1134 - Likewise, for the 2nd fraction, since 81 × 14 = 1134,
90/81 = 90 × 14/81 × 14 = 1260/1134 - Add the two like fractions:
540/1134 + 1260/1134 = 540 + 1260/1134 = 1800/1134 - 1800/1134 simplified gives 100/63
- So, 20/42 + 90/81 = 100/63
In mixed form: 137/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42+90/81 20/84+90/81 60/42+90/81