Why is the Hole below a Lock?

If eleven plus two equals one, what does nine plus five equal?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Identify the 10 differences between the two given pictures.

I have feet, but no legs. Which animal Am I?

Jigsaw captured 100 people and make them stand in a circle and all these people are labelled as Person1, Person2, Person3... Person100. He made them play a crazy game in which Person 1 shot Person 2 and pass the gun to the next person and so on until one stands alive.

Which person will survive in the end?

What occurs twice in a week, once in a year but never in a day?

What is the fastest way to double your money?

Using Only Five 5's and any mathematical operator make sum as 37