Problem 6: Counting Down Beans
Basically, this game is connected to subtraction as we count backwards. As we take away the bean from the pile, we do mental calculation and call out the existing amount of bean that is left on the table. It is a very interesting game as this is the "play stage" theory by Dienes. The children will be able to play the game without consciously knowing that they are learning about subtraction and doing counting back.
Game Instructions: Taking a set amount of beans of about 20 in our case, we are only allowed to removed 1 or 2 beans per turn, between the 2 players. The last player who takes the last bean will win.
Throughout the game, I did mental calculation and tried to control the possibility of winning by ensuring that I have either 5 or 3 beans left so that it will be to my advantage. That is when I realized from Dr Yeap that there are good and bad numbers that can control the winning situation.
I realized that if I take a maximum of 3 beans, the bad number would be in multiples of 4 and if we take maximum of 4 beans, then the bad numbers would be in multiples of 5. The bad numbers would be +1 of the actual maximum no. of bean we are taking.
My group tried playing with all the beans that were given, around 66 beans in all and we removed to a maximum of 5 beans among 3 players. At the beginning, I just try to clear as many bean as possible until it reaches around 12, I became more cautious and strategized the number of beans would take.
The red bean game reminds me of the game
which I played when I was young. We draw
lines into a pyramid and starts canceling, as
you can see from the picture on the left. It was a fun game. And never did realized until now that I was actually learning subtraction!!
How Many were going to Saint Ives?
Subitize: It's the ability to perceive a number of items without actually counting it. Manyness: The quality of being many or a lot.