2. Prime and Composite Numbers

Prime and composite numbers

Understand prime and composite numbers. A prime number has only 2 factors, the number 1 and itself. A composite number has more than factors. It is a common misconception to consider number 1 as prime, whereas it is neither prime nor composite. Another misconception is that all prime numbers are odd (2 is both prime and even).

Common Core Alignment

4.OA.4Find all factor pairs for a whole number in the range 1—100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1—100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1—100 is prime or composite.