Add 21/90 and 81/12
1st number: 21/90, 2nd number: 6 9/12
21/90 + 81/12 is 419/60.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 12 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
21/90 = 21 × 2/90 × 2 = 42/180 - Likewise, for the 2nd fraction, since 12 × 15 = 180,
81/12 = 81 × 15/12 × 15 = 1215/180 - Add the two like fractions:
42/180 + 1215/180 = 42 + 1215/180 = 1257/180 - 1257/180 simplified gives 419/60
- So, 21/90 + 81/12 = 419/60
In mixed form: 659/60
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90+81/12 21/90+81/24 63/90+81/12 21/90+81/36 21/90+81/60 21/90+81/84