Add 3/9 and 3/21
3/9 + 3/21 is 10/21.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 9 and 21 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 9 × 7 = 63,
3/9 = 3 × 7/9 × 7 = 21/63 - Likewise, for the 2nd fraction, since 21 × 3 = 63,
3/21 = 3 × 3/21 × 3 = 9/63 - Add the two like fractions:
21/63 + 9/63 = 21 + 9/63 = 30/63 - 30/63 simplified gives 10/21
- So, 3/9 + 3/21 = 10/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/9+3/21 3/9+6/21 3/18+3/21 3/9+3/42 3/9+9/21 3/27+3/21 3/9+3/63 15/9+3/21 3/9+15/21 3/45+3/21 21/9+3/21 3/63+3/21