A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

It belongs to you, but other people use it more than you do. What is it?

A mother bought three dress for her triplets daughters(one for each) and put the dresses in the dark. One by one the girls come and pick a dress.
What is the probability that no girl will choose her own dress?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

What type of tree can I carry in my hand?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

Why is the Hole below a Lock?

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?