Add 21/8 and 9/21
1st number: 2 5/8, 2nd number: 9/21
21/8 + 9/21 is 171/56.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
21/8 = 21 × 21/8 × 21 = 441/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
9/21 = 9 × 8/21 × 8 = 72/168 - Add the two like fractions:
441/168 + 72/168 = 441 + 72/168 = 513/168 - 513/168 simplified gives 171/56
- So, 21/8 + 9/21 = 171/56
In mixed form: 33/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/8+9/21 21/8+18/21 21/16+9/21 21/8+9/42 63/8+9/21 21/8+27/21 21/24+9/21 21/8+9/63 21/8+45/21 21/40+9/21 21/8+63/21 21/56+9/21