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]

Groups of two to twelve dots, showing that the composite numbers of dots (4, 6, 8, 9, 10, and 12) can be arranged into rectangles but the prime numbers cannot
Prime numbers are natural numbers greater than one that are not products of two or more smaller numbers.

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

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  1. Wikipedia: Prime number
  2. Wikipedia: Generating primes

Multimedia

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  1. YouTube: Prime Numbers and Composite Numbers
  2. YouTube: Prime Numbers - Sieve of Eratosthenes

Activities

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  1. Review MathsIsFun: Prime and Composite Numbers. Create a list of prime numbers less than 100.
  2. 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.
  3. Review Wikipedia: Generating primes and ExtendOffice: How to Generate Prime Numbers in Excel. Use Excel to create your own prime number generator.
  4. Review Wikipedia: Generating primes and Prime number generators. Write your own program to generate prime numbers.

Resources

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See Also

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References

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