Add 21/7 and 18/20
1st number: 3 0/7, 2nd number: 18/20
21/7 + 18/20 is 39/10.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 20 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 7 × 20 = 140,
21/7 = 21 × 20/7 × 20 = 420/140 - Likewise, for the 2nd fraction, since 20 × 7 = 140,
18/20 = 18 × 7/20 × 7 = 126/140 - Add the two like fractions:
420/140 + 126/140 = 420 + 126/140 = 546/140 - 546/140 simplified gives 39/10
- So, 21/7 + 18/20 = 39/10
In mixed form: 39/10
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/7+18/20 21/7+36/20 21/14+18/20 21/7+18/40 63/7+18/20 21/7+54/20 21/7+18/60 21/7+90/20 21/35+18/20 21/49+18/20