Add 7/21 and 28/90
7/21 + 28/90 is 29/45.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
7/21 = 7 × 30/21 × 30 = 210/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
28/90 = 28 × 7/90 × 7 = 196/630 - Add the two like fractions:
210/630 + 196/630 = 210 + 196/630 = 406/630 - 406/630 simplified gives 29/45
- So, 7/21 + 28/90 = 29/45
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/21+28/90 7/21+56/90 7/42+28/90 7/21+84/90 7/63+28/90 35/21+28/90 49/21+28/90