Chapter 7 - Section 7.4 - Adding, Subtracting, and Multiplying Radical Expressions - Exercise Set - Page 439: 35

$\dfrac{2\sqrt{3}}{3}$

Using the properties of radicals, then, \begin{array}{l} \dfrac{4\sqrt{3}}{3}-\dfrac{\sqrt{12}}{3} \\\\= \dfrac{4\sqrt{3}}{3}-\dfrac{\sqrt{4\cdot3}}{3} \\\\= \dfrac{4\sqrt{3}}{3}-\dfrac{2\sqrt{3}}{3} \\\\= \dfrac{2\sqrt{3}}{3} .\end{array}