Find the least number with four digits which is a perfect square

To do: To find the least number with four digits which is a perfect square.

The least $4$ digit number$=1000$

Since, $( 31)^2<1000$

We take, the next perfect square number i.e., $(32)^2= 1024$

$\therefore 1024$ is the required least number $4$ digit number which is a perfect square.