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Prime numbers are positive whole numbers that are only divisible by 1 and themselves.
5 is prime because it can only be evenly divided by 5 and 1. 12 is not prime (meaning it’s a composite number) because it can be evenly divided by 1, 2, 3, 4, 6, and 12.
Using algorithms, it is relatively simple to determine if a number is prime. Although there are infinitely many primes, there is no simple formula to separate prime numbers from composite numbers.
Do you notice anything different about the prime numbers (black boxes) when organized in even multiples? Prime multiples? Multiples of 5? Squares of primes?