Add 30/15 and 18/21
1st number: 2 0/15, 2nd number: 18/21
30/15 + 18/21 is 20/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
30/15 = 30 × 7/15 × 7 = 210/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
18/21 = 18 × 5/21 × 5 = 90/105 - Add the two like fractions:
210/105 + 90/105 = 210 + 90/105 = 300/105 - 300/105 simplified gives 20/7
- So, 30/15 + 18/21 = 20/7
In mixed form: 26/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/15+18/21 30/15+36/21 30/15+18/42 90/15+18/21 30/15+54/21 30/45+18/21 30/15+18/63 30/15+90/21 30/75+18/21