Here is a Montessori Math game that I first heard about in a book called Montessori play and learn by Lesley Britton. I couldn't find the game to buy so I asked a local woodcarver to make it for me. I have since found that it can be purchased from a website called Montessori door to door. It's really very simple to play, you have the game board with 22 bored game piece spots, 11 on each side. A twelve sided dice w/ numbers 1-12, and the little wooden game numerals 0-10, notice in the 2nd picture I put dots corresponding to the number on the opposite side for counting skills.
Here are the directions taken from the Montessori door to door website. : Pickin is an arithmetic game which makes practice of simple addition and subtraction fun. This game is ideal for either home or classroom use and is well suited for children between the ages of 4 and 8. Any child who is having difficulty memorizing simple combinations will find Pickin a challenging game that will aid them in arithmetic and memory skills. Place the wooden discs in order from 0-10 in a row on one side of the board. Throw the die to see who starts. Now the first player throws the dice and then chooses one or more discs that by itself or in combinatins add up to the value of the throw. The player places these discs in his row and continues to throw the die until he can no longer make a combination or find one disc that equals the value of his throw. The next player throws the die and makes up sums from the numbers until he comes to an amount which cannot be made from the remaining numbers. If he doesn't have numbers sufficient for this the turn passes to the next player. The game continues in this manner until all the discs are on one side of the board. The player with all the discs wins. The same process can be used with subtraction differences. Throw the die and choose the one number or any combinations of numbers that when subtracted equal the value of the die. Children who become familiar with the game may go on to inventing new games to be played with this versatile material.