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Prime numbers n1d

Prime numbers

Definition: A prime number is a positive integer that has no positive integer divisors other than and itself. More concisely, a prime number is a positive integer having exactly one positive divisor other than , meaning it is a number that cannot be factored. Positive integers other than 1 which are not prime are called composite numbers. Example: the only divisors of are and , making a prime number, while the number has divisors , and (corresponding to the factorization ), making not a prime number.

Formative assessment

The purpose of the applet below is to sort out prime numbers from composite numbers. Click on the squares that contain prime numbers and then click on check. Try it as many times as you may need.