$$\frac{9}{12}+\frac{2}{12}-\frac{2}{3}$$
Since $\frac{9}{12}$ and $\frac{2}{12}$ have the same denominator, add them by adding their numerators.$$\frac{9+2}{12}-\frac{2}{3}$$
Add $9$ and $2$ to get $11$.$$\frac{11}{12}-\frac{2}{3}$$
Least common multiple of $12$ and $3$ is $12$. Convert $\frac{11}{12}$ and $\frac{2}{3}$ to fractions with denominator $12$.$$\frac{11}{12}-\frac{8}{12}$$
Since $\frac{11}{12}$ and $\frac{8}{12}$ have the same denominator, subtract them by subtracting their numerators.$$\frac{11-8}{12}$$
Subtract $8$ from $11$ to get $3$.$$\frac{3}{12}$$
Reduce the fraction $\frac{3}{12}$ to lowest terms by extracting and canceling out $3$.$$\frac{1}{4}$$