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

Who is that with a neck and no head, two arms and no hands? What is it?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

When can we add 2 to 11 and get 1 as the correct answer?

When it's bad luck to meet a black cat?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

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

A man dies of old age on his 25 birthday. How is this possible?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?