Add 72/21 and 84/63
1st number: 3 9/21, 2nd number: 1 21/63
72/21 + 84/63 is 100/21.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 63 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
72/21 = 72 × 3/21 × 3 = 216/63 - Likewise, for the 2nd fraction, since 63 × 1 = 63,
84/63 = 84 × 1/63 × 1 = 84/63 - Add the two like fractions:
216/63 + 84/63 = 216 + 84/63 = 300/63 - 300/63 simplified gives 100/21
- So, 72/21 + 84/63 = 100/21
In mixed form: 416/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/42+84/63 72/63+84/63