Hi Jodi - i don't know if you've heard of the Learning Ladder, but they sell a Starter Stile set, with Pre-Number, Early Number and then moves onto different levels as the children progress.
If you want to have a look, google the learning ladder - have a look at the online catalogue on pages 34/35. I bought them for my older girls, and am using them now with my almost 3 year old (just starting off with the basics)
It's worth having a look.
(i'm not a learning ladder rep or anything lol)