Add 72/21 and 60/40
1st number: 3 9/21, 2nd number: 1 20/40
72/21 + 60/40 is 69/14.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
72/21 = 72 × 40/21 × 40 = 2880/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
60/40 = 60 × 21/40 × 21 = 1260/840 - Add the two like fractions:
2880/840 + 1260/840 = 2880 + 1260/840 = 4140/840 - 4140/840 simplified gives 69/14
- So, 72/21 + 60/40 = 69/14
In mixed form: 413/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/42+60/40 72/21+60/80 72/63+60/40