You can see it everyday, But cannot touch it at will. What is it?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

Can you spot the man between the coffee bean in the picture below ?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Can you count the number of triangles in the picture below?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

The barber of Town shaves all men living in the town. No man living in the town is allowed to shave himself. The barber lives in that town. Who then shaves the barber of the town?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?