Khan Academy
Khan Academy: Identify Prime Numbers
Identify prime numbers less than 100. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Relatively Prime Numbers and Polynomials
Find a quick, concise explanation of relatively prime numbers and how this concept applies to polynomials. Examples are given and clearly explained.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: The Prime Page
Find a quick, concise but complete explanation of prime numbers. A variety of related topics are covered such as: A table of the first 400 Prime Numbers, Do Primes ever stop?, the Prime Number Theorem and Twin Primes.
Khan Academy
Khan Academy: Prime and Composite Numbers Intro
Discusses factors, prime and composite numbers, and why the number 1 is not prime or composite. Includes practice problems throughout, along with explanations of solutions.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Composite Numbers
Find a quick, concise explanation of Composite Numbers. Several examples are given and clearly explained. Prime numbers are also described.
Wyzant
Wyzant: Prime Number List
WyzAnt provides a list of the prime numbers. The user decides how many primes to see and in what fashion--horizontally or vertically and in how many rows.
Khan Academy
Khan Academy: Identify Composite Numbers
Identify composite numbers less than 100. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Numeros Primos
This interactive unit explain what prime numbers are and how to find them. It also discuss the Sieve of Eratosthenes and the Mersenne number.
Wyzant
Wyzant: Prime Factors Calculator
Students input a number to be factored and the WyzAnt calculator does the rest. Limitations include the fact that numbers which are negative or which contain primes bigger than 541 cannot be handled.
Cool Math
Coolmath: Pre Algebra: Prime Factorizations
In this tutorial, students learn how to do prime factorization by a few different methods, including factor trees and factor stacks. The exercises work their way up from 2-digit numbers up to 5 digits. Includes practice problems.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Prime Factorization
Find a quick, concise explanation of how to find the unique prime factorization of a number. An example is given and clearly explained.
Shmoop University
Shmoop: Basic Operations: Prime Factorization
Students learn about prime factorization. The resource consists of notes, step-by-step examples, and practice problems with solutions.
Other
The Prime Glossary: Rational Numbers
This site gives a definition of what a rational number is. Gives examples and formulas. Very helpful.
Wolfram Research
Wolfram Mathworld: Polynomial Factorization
This site discusses factoring of polynomials, giving a general definition, and many links to satisfy unfamiliar terminology. There are however very few examples.