Prime numbers
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![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](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f0/Primes-vs-composites.svg/220px-Primes-vs-composites.svg.png)
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
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[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.