Add 21/90 and 9/21
21/90 + 9/21 is 139/210.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
21/90 = 21 × 7/90 × 7 = 147/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
9/21 = 9 × 30/21 × 30 = 270/630 - Add the two like fractions:
147/630 + 270/630 = 147 + 270/630 = 417/630 - 417/630 simplified gives 139/210
- So, 21/90 + 9/21 = 139/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90+9/21 21/90+18/21 21/90+9/42 63/90+9/21 21/90+27/21 21/90+9/63 21/90+45/21 21/90+63/21