Add 20/18 and 72/21
1st number: 1 2/18, 2nd number: 3 9/21
20/18 + 72/21 is 286/63.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
20/18 = 20 × 7/18 × 7 = 140/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
72/21 = 72 × 6/21 × 6 = 432/126 - Add the two like fractions:
140/126 + 432/126 = 140 + 432/126 = 572/126 - 572/126 simplified gives 286/63
- So, 20/18 + 72/21 = 286/63
In mixed form: 434/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/18+72/21 20/36+72/21 20/18+72/42 60/18+72/21 20/54+72/21 20/18+72/63 20/90+72/21