Add 45/84 and 72/20
1st number: 45/84, 2nd number: 3 12/20
45/84 + 72/20 is 579/140.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 84 × 5 = 420,
45/84 = 45 × 5/84 × 5 = 225/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
72/20 = 72 × 21/20 × 21 = 1512/420 - Add the two like fractions:
225/420 + 1512/420 = 225 + 1512/420 = 1737/420 - 1737/420 simplified gives 579/140
- So, 45/84 + 72/20 = 579/140
In mixed form: 419/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/84+72/20 45/84+72/40 45/84+72/60