Add 21/12 and 18/45
1st number: 1 9/12, 2nd number: 18/45
21/12 + 18/45 is 43/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 45 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 12 × 15 = 180,
21/12 = 21 × 15/12 × 15 = 315/180 - Likewise, for the 2nd fraction, since 45 × 4 = 180,
18/45 = 18 × 4/45 × 4 = 72/180 - Add the two like fractions:
315/180 + 72/180 = 315 + 72/180 = 387/180 - 387/180 simplified gives 43/20
- So, 21/12 + 18/45 = 43/20
In mixed form: 23/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12+18/45 21/12+36/45 21/24+18/45 21/12+18/90 63/12+18/45 21/12+54/45 21/36+18/45 21/12+90/45 21/60+18/45 21/84+18/45