I’m tall when I’m young, and I’m short when I’m old. What am I?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

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?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

Find the next number in the following series:
6, 14, 26, 98, __?

What has no start, end, or centre?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

You need to arrange three 7 and mathematical symbols to form number 1?