If nine thousand, nine hundred nine dollars is written as $9,909, how should twelve thousand, twelve hundred twelve dollars be written?
How can a man go eight days without sleep?
How could a baby fall out of a twenty-story building onto the ground and live?
A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?
What numbers should go on the bottom line? 3 6 9 15 8 2 10 12 11 8 19 27 19 10 29 39 ? ? ? ?
Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.
Keyboard words are not in alphabetical order, Why?
A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?
How is a fly different from a mosquito?
I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?
What has many keys but can’t open a single lock?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.
