Add 28/90 and 1/21
28/90 + 1/21 is 113/315.
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,
28/90 = 28 × 7/90 × 7 = 196/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
1/21 = 1 × 30/21 × 30 = 30/630 - Add the two like fractions:
196/630 + 30/630 = 196 + 30/630 = 226/630 - 226/630 simplified gives 113/315
- So, 28/90 + 1/21 = 113/315
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/90+1/21 28/90+2/21 28/90+1/42 84/90+1/21 28/90+3/21 28/90+1/63 28/90+5/21 28/90+7/21