This is a homework problem I came across for my discrete math class and I can't manage to figure out the answer. I know it is asking for an example where $m$ and $n$ are positive real numbers, $m$ is less than $n$, and $\sqrt{n}$ is less than or equal to $\sqrt{m}$.
Find a counterexample to the following statement: “If $m$ and $n$ are positive real numbers and $m < n$, then $\sqrt{m} < \sqrt{n}$."
Since $$\sqrt{m}-\sqrt{n}=\frac{(\sqrt{m}-\sqrt{n})(\sqrt{m}+\sqrt{n})}{\sqrt{m}+\sqrt{n}}=\frac{m-n}{\sqrt{m}+\sqrt{n}}<0,$$ we have no the needed counterexample.