Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

Who has married many women but was never married?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

Can you name an animal whose killing cannot be performed without spilling your own blood?

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

Move three sticks of the spiral below to form a square.

A man was just doing his job when his suit was torn. Why did he die three minutes later?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

What does Alexander the Great and Winnie the Pooh have in common?

What has to be broken before you can use it?