Answer
$0$
Work Step by Step
Since $\cot{\theta}= \dfrac{\cos{\theta}}{\sin{\theta}}$
Then,
$\dfrac{\cos{20^{\circ}}}{\sin{20^{\circ}}} = \cot{20^{\circ}}$
Therefore,
$\cot{20^{\circ}} - \dfrac{\cos{20^{\circ}}}{\sin{20^{\circ}}} = \cot{20^{\circ}} - \cot{20^{\circ}} = \boxed{0}$
