Prime and Composite Anchor Chart {plus a freebie!}

Prime and Composite Numbers:
An anchor chart with a mnemonic device to help your students remember the difference!
Prime and Composite Numbers Anchor Chart- This blog post also includes a free practice worksheet!

This anchor chart is the result of a couple inspirations. The first one was Kayla's weekly math homework.  Kayla's fourth grade teacher sends home a sheet of 16 math problems each week, and her students have to complete them and bring the sheet back to school on Thursday (which I think is a great idea!).  The problems vary- addition and subtraction with regrouping, perimeter & area, graphs, story problems- it is obviously designed to spiral.  Also, without fail, there is an Is this number prime or composite? question somewhere on each sheet.  Back in September, Kayla hadn't learned this yet, so she asked me to help.  Full disclosure here.... I was pretty sure I knew what the terms meant, but it had been a while since I had helped anyone above third grade with math, so I had to look the words up on the Internet.  (My recollection was correct, though!)

The second homework sheet came home and the prime and composite question appeared... and Kayla couldn't remember what the words meant.  That's when I pointed out that the letter I looked like the number 1, and that the word "prime" contains the word "me" within it.  I wrote 
PRime= 1 + ME
on Kayla's paper, and explained that a prime number might state, "My factors are 1 and me."  This clicked with Kayla, and she has never since forgotten what the terms prime and composite means.

The second inspiration came from Pinterest.  Have you seen the factor rainbow idea before?  I found it a couple of months ago, and I loved it!  I knew that I wanted to add this idea to my anchor chart, too.  The first image I pinned came from Dandelions and Dragonflies and I think it's such a great strategy to teach students! 
Lots of great math notebook ideas including this one for creating "factor rainbows."

Do you teach your students the difference between prime and composite numbers?  Click on the image below to download this FREE practice worksheet.
Prime and Composite Numbers FREE

Also, I created the following craftivity, which is available in my TpT store.

Thanks for visiting my blog today! 


  1. I LOVE the Prime is PR 1 and me. As a teacher who has taught this concept I never thought of that before. Thanks for sharing.

  2. Hi Deb. I love this Prime trick - never heard or seen it before! I'm happy I got to link up this week!

  3. Love the worksheet! Thanks for sharing!