\[\boxed{\mathbf{525\ (525).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\frac{2}{3}\sqrt{45} = \frac{2}{3} \cdot 3\sqrt{5} = 2\sqrt{5};\]
\[2)\frac{1}{2}\sqrt{128} = \frac{1}{2} \cdot 8\sqrt{2} = 4\sqrt{2};\]
\[3)\frac{1}{10}\sqrt{200} = \frac{1}{10} \cdot 10\sqrt{2} = \sqrt{2};\]
\[4) - 0,05\sqrt{4400} =\]
\[= - 0,05 \cdot 20\sqrt{11} = - \sqrt{11}.\]