Add 21/9 and 8/7, Solve 2 3/9 + 1 1/7 as a fraction

Add 21/9 and 8/7

1^st number: 2 3/9, 2^nd number: 1 1/7

21/9 + 8/7 is 73/21.

Find the least common denominator or LCM of the two denominators:
LCM of 9 and 7 is 63

Next, find the equivalent fraction of both fractional numbers with denominator 63
For the 1st fraction, since 9 × 7 = 63,
21/9 = 21 × 7/9 × 7 = 147/63
Likewise, for the 2nd fraction, since 7 × 9 = 63,
8/7 = 8 × 9/7 × 9 = 72/63
Add the two like fractions:
147/63 + 72/63 = 147 + 72/63 = 219/63
219/63 simplified gives 73/21
So, 21/9 + 8/7 = 73/21
In mixed form: 310/21

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad