Definition
Prime number
A prime number is a whole number greater than 1 with exactly two positive factors.
Continue from this idea into connected AXIO math.
Boundary check: Seventeen has only the factor pair 1 × 17; one itself is not prime.
What it means
A prime number has just one factor pair: 1 and itself. Try to arrange that many objects in equal rows. Apart from a 1-by-the-number row, no other whole-number rectangle works.
Remember it
Prime has one factor pair only: 1 and itself.
Example
Seventeen is prime. Its only positive factors are 1 and 17, so the only whole-number factor pair is 1 × 17.
Watch for
The number 1 is not prime because it has only one positive factor. Two is prime and is the only even prime number.
Common mix-up
Odd does not always mean prime. Nine is odd but composite because 9 = 3 × 3.
Exact meaning
A prime number is a whole number greater than 1 whose only positive factors are 1 and the number itself.