First part of ans is obtained in four steps.
First Part :- Square the first digit of the given number.
Second Part :- Find the product of first two digits and double it.
Third Part :- Add 5 times first digit to square of second digit.
Fourth Part :- 5 times the second digit.
Last Part of ans will be always 25 squared =625.
In general :- pk25 squared =?
=p^2 /2pk /5p +k^2 /5k /625
Consider for example :-
1325 squared = 1^2 /2 (1)(3) / 5 (1)+3^2 /5 (3)/625
It is simple
Posted by Praveenkumar P K