I have fallen in love with the site My Montessori Journey, so you will see a lot of ideas from there. Here is another great idea I borrowed.
For this game, there are little cards with apples on them. They have between 0 and 10 apples. Mustang had to pick a card and then color that many apples on her tree. When she was done, there where 100 colored apples. On My Montessori Journey, she suggests laminating the tree, and I intend to do that when I have a laminator.