Add 20/72 and 21/90
20/72 + 21/90 is 23/45.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 90 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
20/72 = 20 × 5/72 × 5 = 100/360 - Likewise, for the 2nd fraction, since 90 × 4 = 360,
21/90 = 21 × 4/90 × 4 = 84/360 - Add the two like fractions:
100/360 + 84/360 = 100 + 84/360 = 184/360 - 184/360 simplified gives 23/45
- So, 20/72 + 21/90 = 23/45
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/72+21/90 20/72+42/90 60/72+21/90 20/72+63/90