Add 15/21 and 21/5
1st number: 15/21, 2nd number: 4 1/5
15/21 + 21/5 is 172/35.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
15/21 = 15 × 5/21 × 5 = 75/105 - Likewise, for the 2nd fraction, since 5 × 21 = 105,
21/5 = 21 × 21/5 × 21 = 441/105 - Add the two like fractions:
75/105 + 441/105 = 75 + 441/105 = 516/105 - 516/105 simplified gives 172/35
- So, 15/21 + 21/5 = 172/35
In mixed form: 432/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+21/5 15/21+42/5 15/42+21/5 15/21+21/10 45/21+21/5 15/21+63/5 15/63+21/5 15/21+21/15 75/21+21/5 15/21+21/25 15/21+21/35