When I get multiplied by any number, the sum of the figures in the product is always me. What am I?
2, 3, 5, 9, 17, _ What is the next number in the sequence?
How do you go from 98 to 720 using just one letter?
If eleven plus two equals one, what does nine plus five equal?
How many sides does a circle have?
How many times can you subtract the number 5 from 25?
One is to three as three is to five and five is to four and four is the magic number. What is the pattern?
81 x 9 = 801. What must you do to make the this equation true?
If 1+9+8=1, what is 2+8+9?
When my father was 31 I was 8. Now he is twice as old as me. How old am I?
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.
