Add 15/21 and 25/28
15/21 + 25/28 is 45/28.
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,
15/21 = 15 × 4/21 × 4 = 60/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
25/28 = 25 × 3/28 × 3 = 75/84 - Add the two like fractions:
60/84 + 75/84 = 60 + 75/84 = 135/84 - 135/84 simplified gives 45/28
- So, 15/21 + 25/28 = 45/28
In mixed form: 117/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+25/28 15/21+50/28 15/42+25/28 15/21+25/56 45/21+25/28 15/21+75/28 15/63+25/28 15/21+25/84 75/21+25/28