Can you arrange four 9's and use at most 2 math symbols, to make the total 100?
As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?
What question can you never answer yes to?
What number does the below three word/phrase identify and why? 1. Deck 2. Year 3. Singing in the Rain
Can you spot what's wrong with the following sentence? PETER WAS ANGRY AT HIMSELF BECAUSE HE ACCIDENTALLY LEFT THE THE KEYS TO HIS CAR AT HIS FRIEND'S HOUSE.
You are in a room with no metal objects except for two iron rods. Only one of them is a magnet. How can you identify which one is a magnet?
What can you see in the middle of March and April that you can never see in any other month?
What is in seasons, seconds, centuries and minutes but not in decades, years or days?
Which letter of the alphabet has the most water?
What kind of band never plays music?
There is a box full of marbles, all but two are blue, all but two are green, and all but two are red. How many marbles are in the box?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.