Add 42/21 and 81/28
1st number: 2 0/21, 2nd number: 2 25/28
42/21 + 81/28 is 137/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 28 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
42/21 = 42 × 4/21 × 4 = 168/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
81/28 = 81 × 3/28 × 3 = 243/84 - Add the two like fractions:
168/84 + 243/84 = 168 + 243/84 = 411/84 - 411/84 simplified gives 137/28
- So, 42/21 + 81/28 = 137/28
In mixed form: 425/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21+81/28 42/21+81/56 42/63+81/28 42/21+81/84