Add 21/5 and 18/8
1st number: 4 1/5, 2nd number: 2 2/8
21/5 + 18/8 is 129/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 8 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 5 × 8 = 40,
21/5 = 21 × 8/5 × 8 = 168/40 - Likewise, for the 2nd fraction, since 8 × 5 = 40,
18/8 = 18 × 5/8 × 5 = 90/40 - Add the two like fractions:
168/40 + 90/40 = 168 + 90/40 = 258/40 - 258/40 simplified gives 129/20
- So, 21/5 + 18/8 = 129/20
In mixed form: 69/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/5+18/8 21/5+36/8 21/10+18/8 21/5+18/16 63/5+18/8 21/5+54/8 21/15+18/8 21/5+18/24 21/5+90/8 21/25+18/8 21/5+18/40 21/35+18/8 21/5+18/56