Add 20/90 and 8/21
20/90 + 8/21 is 38/63.
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,
20/90 = 20 × 7/90 × 7 = 140/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
8/21 = 8 × 30/21 × 30 = 240/630 - Add the two like fractions:
140/630 + 240/630 = 140 + 240/630 = 380/630 - 380/630 simplified gives 38/63
- So, 20/90 + 8/21 = 38/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/90+8/21 20/90+16/21 20/90+8/42 60/90+8/21 20/90+24/21 20/90+8/63 20/90+40/21 20/90+56/21