find the least 4 digit number which is a perfect square

First we take square root of least 4 digit no. i.e. 1000 by long division method.We get quotient 31 and remainder 39 , Therefore,31's square = 1000-39=961 so no. next to 31 which is 32 whose square is 32x32=1024 is a least 4-digit perfect square.