A word I know has six letters it contains, remove one letter and 12 remain. What is it?
Until it is measured, not known. Yet how you miss it when it has gone. What is it?
Can you find out what is missing? 1 3 5 2 4 ? Hint: It's not six. Think out of the box.
Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3. (You can use one number only once)
Which number should replace the question mark?
How many pluses should we put between the digits of 987654321 to get a total of 99, and where?
If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?
What has 13 hearts but no other organs?
Can you think of any three-dimensional shape that comprises of exactly two surfaces?
Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?
Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.
