How many squares, of any size, can you find on this chessboard which do not contain a Rook?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

Readers with the sharpest vision can find the eagle in the mountains in 6 seconds. Are you one of them? Test your observation skills now!