Teaching Prime Numbers a Different Way

Teaching Prime Numbers a Different Way

Let's consider the positive integers greater than 1, that is 2,3,4,5,..

Suppose we are given the first integer 2 and asked to make all other integers using only the multiply operation.

We soon run into trouble because 2*2=4 and we have no way to make 3.

OK, we just add 3 to our set of given numbers g, so g={2,3}

Can we make 4? Yes, 2*2=4

Can we make 5? No, all our tries fail, so we add 5 to our set of given number g={2,3,5}

Can we make 6? Yes, 2*3=6

Can we make 7? No, all our tries fail, so we add 7 to our given numbers g={2,3,5,7}

Can we make 8? Yes, 2*2*2=8

Can we make 9? Yes, 3*3=9

Can we make 10? Yes, 2*5=10

Can we make 11? No, all our tries fail, so we add it to the set g={2,3,5,7,11}

Can we make 12? Yes, 2*2*3=12

Can we make 13? No, so add it to the set g={2,3,5,7,11,13}

Can we make 14? Yes, 2*7=14

Can we make 15? Yes, 3*5=15

Can we make 16? Yes, 2*2*2*2=16

What is the set g that we are generating by this process? It's the set of prime numbers! This is simply another way to explain prime numbers.

It's a nice demonstration because it shows how prime numbers generate all numbers using only the multiply operation. You can also see that as g gets bigger we can obviously generate more numbers from it, so prime numbers become less and less frequent.

Content written and posted by Ken Abbott abbottsystems@gmail.com