$$\sqrt{10^{2} - 6^{2}} + \sqrt{3^{2} + 4^{2}}=$$． 
Overseas Competition->Knowledge Point->Number Theory Modules->Perfect Square Numbers->Basic Applications of Square Numbers
$$\sqrt{10^{2} - 6^{2}} + \sqrt{3^{2} + 4^{2}}=\sqrt{64} + \sqrt{25} = 8 + 5 = 13$$. 