10+10 and 11+11 can give you the same answer.

Explain how?

What breaks yet never falls, and what falls yet never breaks?

If eleven plus two equals one, what does nine plus five equal?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

You are stuck on an island where you have nothing. You find four pieces of paper somewhere on the island. What will be your strategy to escape from the island safely?

PS: No other resource is available to you on the island, neither can you build anything.

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Four cars come to a four-way stop, each coming from a different direction. They can’t decide who got there first, so they all go forward at the same time. All 4 cars go, but none crash into each other. How is this possible?

Can you tell a 3D object that has just two surfaces?

What runs around the whole yard without moving?

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?