# Prime numbers

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A **prime number** (or a **prime**) is a natural number greater than 1 that cannot be formed by multiplying two or more smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number.^{[1]}

To test for whether a number n is prime, test whether the number is divisible by all integers from 2 to the square root of n.

This method trial division is very slow and can improved by other methods such as the AKS primality test.

## Readings

[edit | edit source]## Multimedia

[edit | edit source]## Activities

[edit | edit source]- Review MathsIsFun: Prime and Composite Numbers. Create a list of prime numbers less than 100.
- Review MathsIsFun: Prime Numbers Chart and Calculator. Compare your list of prime numbers less than 100 for accuracy. Use the prime number calculator to find a prime number greater than 1000.
- Review Wikipedia: Generating primes and ExtendOffice: How to Generate Prime Numbers in Excel. Use Excel to create your own prime number generator.
- Review Wikipedia: Generating primes and Prime number generators. Write your own program to generate prime numbers.