Add 20/45 and 21/70
20/45 + 21/70 is 67/90.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 70 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 45 × 14 = 630,
20/45 = 20 × 14/45 × 14 = 280/630 - Likewise, for the 2nd fraction, since 70 × 9 = 630,
21/70 = 21 × 9/70 × 9 = 189/630 - Add the two like fractions:
280/630 + 189/630 = 280 + 189/630 = 469/630 - 469/630 simplified gives 67/90
- So, 20/45 + 21/70 = 67/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/45+21/70 20/45+42/70 20/90+21/70 60/45+21/70 20/45+63/70