Online College Courses for Credit

Prime and Composite Numbers

Prime and Composite Numbers

Author: Kerrie Meagher
  • I can ​explain whether a whole number is prime, composite or neither by finding the number of factors
  • I can ​explain why a prime number, when modelled as an array, can have only one row

An activity to find the factors of the numbers 1 - 12 and determine whether the numbers are prime or composite

See More

Try Our College Algebra Course. For FREE.

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to many different colleges and universities.*

Begin Free Trial
No credit card required

29 Sophia partners guarantee credit transfer.

312 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 27 of Sophia’s online courses. Many different colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.



  • Write the KEY WORDS and their definitions into your notebook
  • Add your own examples
  • Complete Activity Sheet 1 - Factors of Numbers 1 to 12
  • Answer these questions in your notebook:
  1. ​What is the only even prime number?
  2. Why is 1 neither prime nor composite?
  3. Do all composite numbers have an even number of factors?


Factor: A whole number that divides evenly into another whole number.

Example: 3 and 4 are factors of 12 because 12 ÷ 3 = 4


Prime Number: A whole number that can only be divided evenly by 1 and itself (that is, it has only 2 factors).

Example: 5 is a prime number because it can only be divided evenly by 1 and 5


Composite Number: A whole number than can be divided evenly by more than 2 factors

Example: 10 is a composite number because it can be divided evenly by 1, 2, 5 and 10


Activity Sheet 1 - Factors of Numbers 1 to 12


Source: Kerrie Meagher