Add 81/90 and 90/72
1st number: 81/90, 2nd number: 1 18/72
81/90 + 90/72 is 43/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 72 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 90 × 4 = 360,
81/90 = 81 × 4/90 × 4 = 324/360 - Likewise, for the 2nd fraction, since 72 × 5 = 360,
90/72 = 90 × 5/72 × 5 = 450/360 - Add the two like fractions:
324/360 + 450/360 = 324 + 450/360 = 774/360 - 774/360 simplified gives 43/20
- So, 81/90 + 90/72 = 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: