Add:
(i) $(2 \sqrt{3}-5 \sqrt{2})$ and $(\sqrt{3}+2 \sqrt{2})$
(ii) $(2 \sqrt{2}+5 \sqrt{3}-7 \sqrt{5})$ and $(3 \sqrt{3}-\sqrt{2}+\sqrt{5})$
(iii) $\left(\frac{2}{3} \sqrt{7}-\frac{1}{2}+6 \sqrt{11}\right)$ and $\left(\frac{1}{3} \sqrt{7}+\frac{3}{2} \sqrt{2}-\sqrt{11}\right)$
(i) $2 \sqrt{3}-5 \sqrt{2}+\sqrt{3}+2 \sqrt{2}$
$=(2 \sqrt{3}+\sqrt{3})+(2 \sqrt{2}-5 \sqrt{2})$
$=3 \sqrt{3}-3 \sqrt{2}$
(ii) $2 \sqrt{2}+5 \sqrt{3}-7 \sqrt{5}+3 \sqrt{3}-\sqrt{2}+\sqrt{5}$
$=2 \sqrt{2}-\sqrt{2}+5 \sqrt{3}+3 \sqrt{3}+\sqrt{5}-7 \sqrt{5}$
$=\sqrt{2}+8 \sqrt{3}-6 \sqrt{5}$
(iii) $\frac{2}{3} \sqrt{7}-\frac{1}{2} \sqrt{2}+6 \sqrt{11}+\frac{1}{3} \sqrt{7}+\frac{3}{2} \sqrt{2}-\sqrt{11}$
$=\frac{2}{3} \sqrt{7}+\frac{1}{3} \sqrt{7}-\sqrt{11}+6 \sqrt{11}+\frac{3}{2} \sqrt{2}-\frac{1}{2} \sqrt{2}$
$=\sqrt{7}+5 \sqrt{11}+\sqrt{2}$