Add 4/21 and 72/20
1st number: 4/21, 2nd number: 3 12/20
4/21 + 72/20 is 398/105.
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,
4/21 = 4 × 20/21 × 20 = 80/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
72/20 = 72 × 21/20 × 21 = 1512/420 - Add the two like fractions:
80/420 + 1512/420 = 80 + 1512/420 = 1592/420 - 1592/420 simplified gives 398/105
- So, 4/21 + 72/20 = 398/105
In mixed form: 383/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/21+72/20 4/42+72/20 4/21+72/40 12/21+72/20 4/63+72/20 4/21+72/60 20/21+72/20 28/21+72/20