[tex]a)\\\\ 2^{-2}-5^{-1}= \frac{1}{2^2} -\frac{1}{5^1}=\frac{1}{4}-\frac{1}{5}=\frac{5}{20}-\frac{4}{20}=\frac{1}{20}\\\\b)\\\\\sqrt{200}-\frac{\sqrt{32}}{\sqrt{2}} =\sqrt{100*2}- \sqrt{\frac{32}{2}}=\sqrt{100}*\sqrt{ 2}- \sqrt{16}=10\sqrt{2}-4 =2(5\sqrt{2}-2)[/tex]
