1-1/căn 6 với 1/5 so sánh hai cái
\sqrt{6}>\sqrt{4}=2\Rightarrow \frac{1}{\sqrt{6}}<\frac{1}{2}\Rightarrow -\frac{1}{\sqrt{6}}>-\frac{1}{2}\Rightarrow 1-\frac{1}{\sqrt{6}}>1-\frac{1}{2}=\frac{1}{2}=\frac{5}{10}>\frac{2}{10}=\frac{1}{5}
\\VAY1-\frac{1}{\sqrt{6}}>\frac{1}{5}