Add 2/5 and 15/21
2/5 + 15/21 is 39/35.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 5 × 21 = 105,
2/5 = 2 × 21/5 × 21 = 42/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
15/21 = 15 × 5/21 × 5 = 75/105 - Add the two like fractions:
42/105 + 75/105 = 42 + 75/105 = 117/105 - 117/105 simplified gives 39/35
- So, 2/5 + 15/21 = 39/35
In mixed form: 14/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 4/5+15/21 2/5+30/21 2/10+15/21 2/5+15/42 6/5+15/21 2/5+45/21 2/15+15/21 2/5+15/63 10/5+15/21 2/5+75/21 2/25+15/21 14/5+15/21 2/35+15/21