Add 21/28 and 4/5
21/28 + 4/5 is 31/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 5 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 28 × 5 = 140,
21/28 = 21 × 5/28 × 5 = 105/140 - Likewise, for the 2nd fraction, since 5 × 28 = 140,
4/5 = 4 × 28/5 × 28 = 112/140 - Add the two like fractions:
105/140 + 112/140 = 105 + 112/140 = 217/140 - 217/140 simplified gives 31/20
- So, 21/28 + 4/5 = 31/20
In mixed form: 111/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28+4/5 21/28+8/5 21/56+4/5 21/28+4/10 63/28+4/5 21/28+12/5 21/84+4/5 21/28+4/15 21/28+20/5 21/28+4/25 21/28+28/5 21/28+4/35