What is harder to catch the faster you run?
My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?
What are the 50th, 63rd and 100th numbers in the sequence below? 4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...
The following alphametic has only one solution. Can you find it? ENLIST + SILENT + LISTEN = ANAGRAM PS: You may start the number from 0.
Which is heavier: a ton of bricks or a ton of feathers?
If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?
I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?
John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?" While Bella does not know the answer, do you ?
I’m orange, I wear a green hat and I sound like a parrot. What am I?
Can you circle exactly four of these numbers such that the total is twelve? 1 6 1 6 1 6 1 6 1 6 1 6
Can you move 2 matchsticks to form four equal sized squares.
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.