What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

What makes this number unique: 8,549,176,320?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

A man walked into a pub and went straight towards the Barman. He asked for a dirty martini from the Barman. The Barman thought something and then pulled out a pistol from his drawer and aimed it directly at the man. Why did he do that?

If 1+9+8=1, what is 2+8+9?

How can you throw a ball as hard as you can and have it come back to you even if it doesn't hit anything there is nothing attached to it and no one else catches or throws it.

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Can you find the 09 errors in the picture below?