[tex]\it \dfrac{\sqrt2-1}{\sqrt2}+\dfrac{\sqrt3-\sqrt2}{\sqrt6}+\dfrac{\sqrt4-\sqrt3}{\sqrt{12}}=\dfrac{\sqrt2}{\sqrt2}-\dfrac{1}{\sqrt2}+\dfrac{\sqrt3}{\sqrt6}-\dfrac{\sqrt2}{\sqrt6}+\dfrac{\sqrt4}{\sqrt{12}}-\dfrac{\sqrt3}{\sqrt{12}}=\\ \\ \\ =1-\dfrac{1}{\sqrt2}+\dfrac{1}{\sqrt2}-\dfrac{1}{\sqrt3}+\dfrac{1}{\sqrt{3}}-\dfrac{1}{2}=1-\dfrac{1}{2}=\dfrac{1}{2}[/tex]