1. How to quickly find the square of a number ending with 5:
Example 1- 25²
Step 1: Always right 25 on the right. _25
Step 2: Now multiply the number 2 with it's following number= 2x3=6
Step 3: Answer becomes 625
Example 2- 85²
Step 1: Write 25 on right hand side. _25
Step 2: 8x9= 72
Step 3: Answer= 7225
Example 3- 105²
_25
10x11= 110
Answer= 11025.