The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

You can hear me, but you can't touch or see me.

What am I?

What does this rebus puzzle means ?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

What has a ring but no finger?

I have feet, but no legs. Which animal Am I?

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?

A container contains 100 eggs. They can be either fresh or rotten. What is sure is the fact that there is at least one fresh egg in that container.

If you are asked to pick two eggs randomly from the container, at least one of them will be rotten.

Can you calculate how many eggs in that container are fresh?