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?

I have thought of a number that is made up by using all the ten digits just once. Here are a few clues for you to guess my number:

First digits is divisible by 1.
First two digits are divisible by 2.
First three digits are divisible by 3.
First four digits are divisible by 4.
First five digits are divisible by 5.
First six digits are divisible by 6.
First seven digits are divisible by 7.
First eight digits are divisible by 8.
First nine digits are divisible by 9.
The number is divisible by 10.

Can you find out the number ?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

What breaks yet never falls, and what falls yet never breaks?

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

Can you find the odd number in the following five choices?

1) 482636
2) 259807
3) 865195
4) 104739
5) 391744

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Can you spot the man between the coffee bean in the picture below ?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?