When we see 2 but call 10?
If it took eight men ten hours to build a wall, how long would it take four men to build it?
Prove that twice of ten is the same as twice of eleven.
What number comes next in the series? 5 15 5 18 5 24 14 20 _
Which wheel of car does not rotate when you turn your car right?
Solve this riddle by finding the odd one out from the rest.
The day after tomorrow will be three days before Tuesday. Can you find out what is today?
A professor thinks of two consecutive numbers between 1 and 10. 'A' knows the 1st number and 'B' knows the second number A: I do not know your number. B: Nor do I know your number. A: Now I know. What are the four solutions for this?
You see a boat filled with people, yet there isn’t a single person on board. How is that possible?
If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following: 21 Q 7 R 9 S 10 P 13
It comprises roots which nobody sees, Much taller than those trees, Up and up it goes, Still it never grows?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.