Add 20/21 and 30/42
20/21 + 30/42 is 5/3.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 42 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 21 × 2 = 42,
20/21 = 20 × 2/21 × 2 = 40/42 - Likewise, for the 2nd fraction, since 42 × 1 = 42,
30/42 = 30 × 1/42 × 1 = 30/42 - Add the two like fractions:
40/42 + 30/42 = 40 + 30/42 = 70/42 - 70/42 simplified gives 5/3
- So, 20/21 + 30/42 = 5/3
In mixed form: 12/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21+30/42 20/21+60/42 20/42+30/42 20/21+30/84 60/21+30/42 20/21+90/42 20/63+30/42