First add $\frac{1}{4}$ and $\frac{1}{6}$ by finding a common denominator:

$\frac{1}{4} + \frac{1}{6} = \frac{3}{12} + \frac{2}{12} = \frac{5}{12}$

Then subtract $\frac{1}{3}$:

$\frac{5}{12} - \frac{1}{3} = \frac{5}{12} - \frac{4}{12} = \frac{1}{12}$