Add 21/42 and 90/10
1st number: 21/42, 2nd number: 9 0/10
21/42 + 90/10 is 19/2.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 10 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
21/42 = 21 × 5/42 × 5 = 105/210 - Likewise, for the 2nd fraction, since 10 × 21 = 210,
90/10 = 90 × 21/10 × 21 = 1890/210 - Add the two like fractions:
105/210 + 1890/210 = 105 + 1890/210 = 1995/210 - 1995/210 simplified gives 19/2
- So, 21/42 + 90/10 = 19/2
In mixed form: 91/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/84+90/10 21/42+90/20 63/42+90/10 21/42+90/30 21/42+90/50 21/42+90/70