Add 30/8 and 90/21
1st number: 3 6/8, 2nd number: 4 6/21
30/8 + 90/21 is 225/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
30/8 = 30 × 21/8 × 21 = 630/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
90/21 = 90 × 8/21 × 8 = 720/168 - Add the two like fractions:
630/168 + 720/168 = 630 + 720/168 = 1350/168 - 1350/168 simplified gives 225/28
- So, 30/8 + 90/21 = 225/28
In mixed form: 81/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/8+90/21 30/16+90/21 30/8+90/42 90/8+90/21 30/24+90/21 30/8+90/63 30/40+90/21 30/56+90/21