If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

The host of a game show, offers the guest a choice of three doors. Behind one is a 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?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

I add 5 to 9 and get 2. The answer is correct, so what am I?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

What always comes into a house through the keyhole?

There was a greenhouse.
Inside the greenhouse, there is a white house.
Inside the white house, there is a red house.
Inside the red house, there are lots of babies.

What is It?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.