quan·ti·fy [verb] to determine, indicate, or express the quantity of.
Good old quantifying, one of our friendly math objectives. How do we teach this to preschoolers? Well, we started out with having the children put a button on each flower (to go along with our plant study). As they put each one on, they counted it. So, not only are they counting, but they are counting objects (1:1 correspondence), quantifying (indicating the quantity), and representing the amount with a number symbol. And they just thought they were playing a game!
We had more of these cards all the way up to the number 20.
Then to reinforce the number symbols, we had the children use number sponges and paint to make prints on their paper. We asked them to identify the numbers as they were stamping. Here are some photos of what we did.
The kids had lots of fun with this and made a much smaller mess than I had anticipated!
Here are some books about numbers and counting (and one about comparing sizes: The Best Bug Parade) that might also be helpful.