How often do you have to calculate the square of a number ending in 5? There is a very easy way to calculate the square of numbers ending in 5. In this article, we explain that process to you and also explain the logic behind the trick

Let n5 be the number. n being the ten's digit. 5 is the unit's digit. We need to find the value of (n5)2
The right most two digits would be 25. 
The other digits in the result would be n(n + 1) 

Let's do an example: 25 2 
Step 1: The right two digits are 25 
step 2: n(n + 1) = 2 (2 + 1) = 2 X 3 = 6 
Step 3: Combine the two. The answer is 625. 

Let's do 352
Step 1: The right two digits are 25 
step 2: n(n + 1) = 3 (3 + 1) = 3 X 4 = 12 
Step 3: Combine the two. The answer is 1225. 

Now try these:
452
552
652
752
852
952