Add 21/72 and 20/90
21/72 + 20/90 is 37/72.
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,
21/72 = 21 × 5/72 × 5 = 105/360 - Likewise, for the 2nd fraction, since 90 × 4 = 360,
20/90 = 20 × 4/90 × 4 = 80/360 - Add the two like fractions:
105/360 + 80/360 = 105 + 80/360 = 185/360 - 185/360 simplified gives 37/72
- So, 21/72 + 20/90 = 37/72
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72+20/90 21/72+40/90 63/72+20/90 21/72+60/90