A puzzle that involves and requires knowledge of prime numbers.
A prime number is a natural number that is greater than 1, that cannot be the product of any two smaller natural numbers. It can only be formed, with natural numbers, by multiplying 1 and itself.
There is no way to multiply any two numbers between 1 and 7 (2, 3, 4, 5, 6) together too create seven. The only two natural numbers when multiplied together to create seven are 1 & 7.
A prime puzzle is one that requires knowledge of prime numbers and incorporates them into the puzzle.
The first ten prime numbers are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29
See also number-theory.