Add 21/42 and 6/90
21/42 + 6/90 is 17/30.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
21/42 = 21 × 15/42 × 15 = 315/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
6/90 = 6 × 7/90 × 7 = 42/630 - Add the two like fractions:
315/630 + 42/630 = 315 + 42/630 = 357/630 - 357/630 simplified gives 17/30
- So, 21/42 + 6/90 = 17/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42+12/90 21/84+6/90 63/42+6/90 21/42+18/90 21/42+30/90 21/42+42/90