How many sides does a circle have?

Outside a tattoo artist's shop, there was a signboard which read 'I make tattoos on only them who do not tattoo themselves'.

Reading it what do you think, does the tattoo artist tattoo himself?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

Can you find out the total number of triangles in the given figure?

How many times do a clock's hands overlap in a day ?

Prove that the below maths equation is true.

8 + 8 = 91

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

Find the next number in the sequence

5 12 24 36 ?

Three men in a cafe order a meal the total cost of which is $15. They each contribute $5. The waiter takes the money to the chef who recognises the three as friends and asks the waiter to return $5 to the men.

The waiter is not only poor at mathematics but dishonest and instead of going to the trouble of splitting the $5 between the three he simply gives them $1 each and pockets the remaining $2 for himself.

Now, each of the men effectively paid $4, the total paid is therefore $12. Add the $2 in the waiters pocket and this comes to $14. Where has the other $1 gone from the original $15?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?