Not long ago someone posted this link on the BCAMT list serve. When I first accessed the link I was fascinated as I watched the progression of dots on my screen, each representing the next natural number. The configuration of each number of dots revealed information about the make-up of that particular number.
It made me wish that I had had access to such a visual when I was teaching about factoring, prime numbers, and composite numbers. I thought I would pass the link on to you folks as I know some of you are, indeed, teaching these concepts associated with number theory.
Many of you will be familiar with exploring these particular concepts through the process of creating rectangles from square tiles. In this method, for example, seven can be shown to be prime because seven square tiles can be made into only one rectangle: 7 x 1. Eight, however, can be shown to be composite because eight square tiles can be made into more than one rectangle: 8 x 1 and 4 x 2.
The visual presented here offers another way for students to literally see whether or not a number is prime, and, for those which are not prime, to be able to deduce some or all of the factors from the grouping of the dots.
I hope you will use the link and the accompanying picture here to explore primes, composites, and factors.
PS: Thanks Kelli Holden for commenting on the picture and sending along a link to Malke Rosenfeld’s blog where the picture has been turned into a game! Check out this link.