Add 21/8 and 28/21
1st number: 2 5/8, 2nd number: 1 7/21
21/8 + 28/21 is 95/24.
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,
28/21 = 28 × 8/21 × 8 = 224/168 - Add the two like fractions:
441/168 + 224/168 = 441 + 224/168 = 665/168 - 665/168 simplified gives 95/24
- So, 21/8 + 28/21 = 95/24
In mixed form: 323/24
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/8+28/21 21/8+56/21 21/16+28/21 21/8+28/42 63/8+28/21 21/8+84/21 21/24+28/21 21/8+28/63 21/40+28/21 21/56+28/21