## Basic College Mathematics (9th Edition)

$-\frac{5}{9}$
The numbers 3 and 9 have a least common multiple of 9. Therefore, we can rewrite both fractions with a denominator of 9. $-\frac{2}{3}+\frac{1}{9}=-\frac{2\times3}{3\times3}+\frac{1}{9}=-\frac{6}{9}+\frac{1}{9}=\frac{-6+1}{9}=-\frac{5}{9}$