$$\frac{7\sqrt{3}}{\sqrt{10}+\sqrt{3}}-\frac{3\sqrt{5}}{\sqrt{6}+\sqrt{5}}-\frac{3\sqrt{2}}{\sqrt{15}+3\sqrt{2}}$$
$-\frac{\sqrt{3}\left(\sqrt{6}-\sqrt{5}\right)\left(\sqrt{15}-3\sqrt{2}\right)\left(\sqrt{30}+6\right)}{3}\approx 0.522774425$
$\sqrt{3} {(-\frac{\sqrt{2} \sqrt{3}}{\sqrt{15} + 3 \sqrt{2}} - \frac{\sqrt{3} \sqrt{5}}{\sqrt{5} + \sqrt{6}} + \frac{7}{\sqrt{3} + \sqrt{10}})} = 0.522774425$