Add 21/90 and 8/21
21/90 + 8/21 is 43/70.
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,
8/21 = 8 × 30/21 × 30 = 240/630 - Add the two like fractions:
147/630 + 240/630 = 147 + 240/630 = 387/630 - 387/630 simplified gives 43/70
- So, 21/90 + 8/21 = 43/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90+8/21 21/90+16/21 21/90+8/42 63/90+8/21 21/90+24/21 21/90+8/63 21/90+40/21 21/90+56/21