When I got four, I have it none. When I got two, I have it some. When I got none, I have it all. What is it?
I am an odd number. Take away a letter and I become even. What number am I?
How much will a 38° angle measure when looked at under a microscope that magnifies ten times?
The following alphametic has only one solution. Can you find it? ENLIST + SILENT + LISTEN = ANAGRAM PS: You may start the number from 0.
Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?
What is the word or phrase?
If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten. How is this possible?
What is the longest word in the dictionary?
If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?
How many times in a given day, minutes and hour clock comes in a straight line ?
Which alphabet letter is a question?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.