Square of 2-digit numbers ending with 5

Confused when asked what is 25 square what is 85 square.. Well you won't be after reading this one!!!
This s a simple formula.
25x25=625
Now how's that???
Well,
Let us look at the number 25.
It has 2 at the tens place and 5 at the ones place
Now we will divide the product into 2 parts
The first part will contain the digits at the thousands and hundreds place.
The second part will contain the digits at the tens and ones place.
To find the first part of the answer,
      we have to multiply he number at the tens place i.e. 2 with its successor i.e. 3 which s equal to 6.
      2x3=6
Therefore, the first part of the answer is 06.
To find the second part of the answer,
     we have to take the square of 5 i.e. 25.
     5x5=25
Therefore, the second part of the answer is 25.
That means that the square of 25 is 625.
This works on any 2 digit number ending with 5.