Thank you lovely ladies for your advice! I liked the idea of having a row of five apples the same colour. It will definitely be good for building number sense. So I decided to keep the same colours for all the numbers 0-20. Here's a pic of my cards, all printed and cut, waiting to be laminated!
They're pretty simple, but I think they turned out pretty cute! If you would like a copy for yourself, head on over to my Facebook page. Click the tab that says "Fan Freebies". Then click the picture to go to the Google Docs folder where you will find my Number Posters! Click the picture below to go to my FB page.