Add 21/15 and 45/28
1st number: 1 6/15, 2nd number: 1 17/28
21/15 + 45/28 is 421/140.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 28 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 15 × 28 = 420,
21/15 = 21 × 28/15 × 28 = 588/420 - Likewise, for the 2nd fraction, since 28 × 15 = 420,
45/28 = 45 × 15/28 × 15 = 675/420 - Add the two like fractions:
588/420 + 675/420 = 588 + 675/420 = 1263/420 - 1263/420 simplified gives 421/140
- So, 21/15 + 45/28 = 421/140
In mixed form: 31/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/15+45/28 21/15+90/28 21/30+45/28 21/15+45/56 63/15+45/28 21/45+45/28 21/15+45/84 21/75+45/28