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?

81 x 9 = 801. What must you do to make the this equation true?

You bought me for dinner but never eat me. What am I?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

What has to be broken before you can use it?

No matter how little or how much you use me, you change me every month. What am I?

What does this mean?

CCCCCCC

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?