I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

What can jump higher than a building?

What brings you down but never up?

How many sides does a circle have?

Buy me, smell me or deliver me, I do not change.

Who am I?

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

What is the end of everything?