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

What is so fragile that saying its name breaks it?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

What does does this rebus picture means ?

What's a single-digit number with no value?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

I travel all around the world but always stay in the corner. What am I?

Count the number of lines in the image below ?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?