Add 30/36 and 18/21
30/36 + 18/21 is 71/42.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 36 and 21 is 252
Next, find the equivalent fraction of both fractional numbers with denominator 252 - For the 1st fraction, since 36 × 7 = 252,
30/36 = 30 × 7/36 × 7 = 210/252 - Likewise, for the 2nd fraction, since 21 × 12 = 252,
18/21 = 18 × 12/21 × 12 = 216/252 - Add the two like fractions:
210/252 + 216/252 = 210 + 216/252 = 426/252 - 426/252 simplified gives 71/42
- So, 30/36 + 18/21 = 71/42
In mixed form: 129/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/36+18/21 30/36+36/21 30/72+18/21 30/36+18/42 90/36+18/21 30/36+54/21 30/36+18/63 30/36+90/21