Question 21
Given $x\ne n+0.5$, where $n$ is an integer. Let $[x]$ represent the integer closest to $x$. For example, $[2.4]=2$ and $[2.6]=3$. What is the numerical value of $[\sqrt{1\times2}]+[\sqrt{2\times3}]+[\sqrt{3\times4}]+\ldots+[\sqrt{40\times41}]$?