What is black when you buy it, red when you use it, and gray when you throw it away?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

Prove that the below maths equation is true.

8 + 8 = 91

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

I shave every day, but my beard stays the same. What am I?

Solve the alphametic puzzle by replacing the alphabet with the number.

S T O R M +
S O L E S
=========
T O W E L
=========

What is the fastest way to double your money?

How many letters are in the alphabet?

What does this rebus riddle means ?