Add 81/21 and 70/42
1st number: 3 18/21, 2nd number: 1 28/42
81/21 + 70/42 is 116/21.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 42 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 21 × 2 = 42,
81/21 = 81 × 2/21 × 2 = 162/42 - Likewise, for the 2nd fraction, since 42 × 1 = 42,
70/42 = 70 × 1/42 × 1 = 70/42 - Add the two like fractions:
162/42 + 70/42 = 162 + 70/42 = 232/42 - 232/42 simplified gives 116/21
- So, 81/21 + 70/42 = 116/21
In mixed form: 511/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/42+70/42 81/21+70/84 81/63+70/42