Add 20/21 and 10/90
20/21 + 10/90 is 67/63.
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,
20/21 = 20 × 30/21 × 30 = 600/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
10/90 = 10 × 7/90 × 7 = 70/630 - Add the two like fractions:
600/630 + 70/630 = 600 + 70/630 = 670/630 - 670/630 simplified gives 67/63
- So, 20/21 + 10/90 = 67/63
In mixed form: 14/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21+10/90 20/21+20/90 20/42+10/90 60/21+10/90 20/21+30/90 20/63+10/90 20/21+50/90 20/21+70/90