Find the least nu

We have,

Smallest number of 4 digits = 1000

Using the long division method, we have

From long division method it is clear that, 1000 is not a perfect square and the obtained square root is between 31 and 32

So, by squaring the next integer we will get the perfect square

(32)² = 1024

Thus, 1024 is the smallest four digit perfect square

As,

= 32