Add 70/21 and 81/20
1st number: 3 7/21, 2nd number: 4 1/20
70/21 + 81/20 is 443/60.
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,
70/21 = 70 × 20/21 × 20 = 1400/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
81/20 = 81 × 21/20 × 21 = 1701/420 - Add the two like fractions:
1400/420 + 1701/420 = 1400 + 1701/420 = 3101/420 - 3101/420 simplified gives 443/60
- So, 70/21 + 81/20 = 443/60
In mixed form: 723/60
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 70/42+81/20 70/21+81/40 70/63+81/20 70/21+81/60