Relation between the digit of a perfect square and its square root

Find the least number which must be added to 8400 to obtain a perfect square. Find this perfect square and its square root.

Find the least number which must be added to 6203 to abtain a perfect square. Find this perfect square and its square root.

Find the least number which must be subtracted from 7581 to obtain a perfect square. Find this perfect square and its square root.

What least number must be added to 5607 to make the sum a perfect square ? Fnd this perfect square and its square root.

Find the least number of six digits which is a perfect square. Find the square root of this number.

Find the greatest number of five digits which is perfect square. What is the square root of this number ?

By repeater subtracion of odd numbers from 1,find whether the following numbers are perfect squares or not?If the number is a perfect squar,then,find its square root. 121

By repeated subtraction of odd numbers from 1,find whether the following numbers are perfect squares or not?If the number is a perfect squar,then,find its square root. 49

By repeater subtracion of odd numbers from 1,find whether the following numbers are perfect squares or not?If the number is a perfect squar,then,find its square root. 90