The Square of numbers ending in 5 can be easily calculated in few seconds. In five seconds you will be able to solve in a single line.
The answer comes in two parts. LHS and RHS. The RHS is always 25. Because for all the numbers ending in 5, the last two digits of its square will be 25.
Example 1:
What is Square of 45?
Step 1: Divide 45 into 4 / 5.
Step 2 (LHS): The next consecutive digit of 4 is 5. So Multiply 4 with 5. ie 20.
Step 3: 20/Square of 5 ie 25 (RHS is always 25)
Answer is 2025.
Example 2:
What is the Square of 65?
Step 1: 6 / 5.
Step 2: 6 x 7 = 42. (LHS)
Step 3: 42 / 25
The Answer is 4225
Example 3:
What is the Square of 95?
Step 1: 9 / 5
Step 2: 9 x 10 = 90 (LHS)
Step 3: 90 / 25
The Answer is 9025
Similarly,
Square of 25 = 2 x 3 / 5 x 5 = 6 / 25 = 625.
Square of 125 = 12 x 13/ 5 x 5 = 156 / 25 = 15625.
Square of 505 = 50 x 51/ 5 x 5 = 2550 / 25 = 255025.
