Add 18/21 and 90/20
1st number: 18/21, 2nd number: 4 10/20
18/21 + 90/20 is 75/14.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
18/21 = 18 × 20/21 × 20 = 360/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
90/20 = 90 × 21/20 × 21 = 1890/420 - Add the two like fractions:
360/420 + 1890/420 = 360 + 1890/420 = 2250/420 - 2250/420 simplified gives 75/14
- So, 18/21 + 90/20 = 75/14
In mixed form: 55/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21+90/20 18/42+90/20 18/21+90/40 54/21+90/20 18/63+90/20 18/21+90/60 90/21+90/20