The Montessori Bank Game can be confusing for a couple of reasons. One reason is that it is an elementary work, but some primary teachers call the collective exercises with the golden beads the "bank game" as well. I actually think the name suits the golden beads better. Kal-El aptly stated, "This isn't like going to the bank at all." Homeschooling families may wonder how they are going to do this with perhaps only one child or with the wider mix of ages that can naturally be present in family but not in a Montessori classroom. In truth, this work can be done by anywhere from 1-6 children and 1-6 named jobs can be listed depending on which album you are using. For example, MRD writes up the presentation as if it is being done by one child; Mid America, two; KotU and Cultivating Dharma, three; and my actual bank game set from the manufacture has six job cards (Customer, Clerk, Bookkeeper, Banker, Controller, Cashier).
Basically the bank game is a long multiplication exercise that uses the same steps as the large bead frame except in this case the child uses cards and not an abacus. If the large bead frame work can be done by one child, than the bank game work can be done by one child. My understanding is that it was invented to give the child yet another way to practice long multiplication, particularly this time in a way that caters to the child's desire at this age to work in collaboration with other children. Do not feel pressured to do this work with a particular number of children. It can be done with ANY number from one to ?. The take-away here is that this is a one person job being divided up into as many pieces as suit your purpose and you can divide it up in such a way that someone who is not actually capable of doing the complete work can still participate. It's kind of like the way the government creates jobs.
So rather than being a group game only suitable in traditional Montessori classrooms, the elementary bank game is actually great for homeschoolers because you can recruit your primary kids who are able to read number cards and involve them right along with your eight year old who needs the work and your twelve year old who needs the review but would be too cool to do it if he wasn't helping his little brother. Your child might not NEED another way to practice long multiplication so you might not need this work. Your child might need it, but can do it alone. Your child might need it and do it with you. Your child might need it and do it with siblings or friends. In our house, Me Too needs it but Kal-El does not. Kal-El needs to learn to be a leader and work with others who are still learning so I pulled him in to practice anyway. However, my kids really really dislike each other right now and can't get along. So, in the end, Me Too is better off doing it with me or by himself.
On a typical day in our school room we have two students and one guide. So, we can play this game as a one, two, or three person game. Once we started trying it out, Idecided that if it were going to be divided up it really makes the most sense for us as a two person job. One person is doing the calculating the other is doing the physical work of getting the cards from remote locations. If I have a job, I would call it "referee." I sit nearby and break up all of the arguments. Now, getting cards from the "bank" can involve some exchanging and depending on the abilities of your runner they may or may not be able to do that. In the case of our youngest student, Me Too, he is an old pro at doing long exchanges in his head and does it on his own. If you had a younger child helping the person doing the calculations could just be more specific as to what to bring and/or the exchanging can be broken down into mores steps.
The boys weren't particularly interested in anything called "the bank game." And, as Kal-El said, this is not much like going to the bank. So after the boys refused the presentation a few times I renamed it. In the Star Wars universe, some B'omarr Monks become so enlightened that they no longer required their bodies. Their enlightened brains are surgically removed from their bodies and transferred to nutrient-filled jars, freed from the distractions of life. They sit on shelves meditating and pondering the infinite for centuries. They rarely need to move around the monastery, but when they do their jar can be carried around by a special "spider droid" designed for this purpose.
You will have seen a B'omarr Monk in Star Wars, Return of the Jedi, at Jabba's palace.
So at our house when we play the "B'omarr Monk game" (Bank game) one child is the "brain" and the other is the "spider droid." The brain stays at the working table and does all of the calculating. The "spider droid" runs back and forth to the distant rugs holding the number cards and takes care of moving around the cards on the working table. I replaced the sad little "clerk" and "cashier" cards from our bank game box with cards with the following pictures instead:
If you are as crazy as we are and want to do the bank game this way, here is a link to a Google doc with all of these ready to print. I threw the photo at the top of this post from the Star Wars movie on to the top of our Bank Game box as a label.
Here is our school room set up to start the game. We have two and do the actual work at our black table.
This is our rug with the white cards that are used for the products.
This is our rug that holds the colored cards for the multiplicand and the grey cards for the multiplier.
Our work table happens to already have a category chart under the glass that we use with the stamp game. The boys like to use that chart for this as well. When they get numbers bigger than 9000 they just pretend there are more columns to the left. This was one of our first equations and we started with one-digit multipliers. We progressed from one-digit, to two- and three- digit multipliers the very first day. To the left you can see the the decomposed multiplicand and the grey multiplier card that has been moved alongside. I'll save walking you through an equation with a two- or three-digit multiplier for another day. What I will do right now is describe the division of labor.
We switch jobs among the three of us. Most of the time we play as a two player game with me and one child, not both. Me Too likes all of the jobs. Kal-El would prefer to always be the brain. That makes sense due to his age. He is old enough to be uninterested in moving a bunch of little pieces around.
This is one work for which I felt no desire to have a pack of preprinted equations. After they had an example of each of the different sizes of multipliers, I set them free to invent their own equations. So, when we play the game, The Brain invents the equation and asks the The Droid to bring him the colored cards he needs for the multiplicand. Then, he asks him to bring him the grey cards he needs for the multiplier. Next, he asks The Droid to "do the magic slide" with the multiplicand cards so he can verify the number. Then, he asks The Droid to decompose the multiplier. We don't have a set person responsible for moving the grey cards around as needed during the game. Often I do it if I'm playing the referee because I'm sitting right next to the cards. However, either The Brain or The Droid could be the one to move the cards. Technically The Droid should do it because The Brain has no arms.
The Brain continues his work by doing the calculations and asking The Droid to bring him the product cards he needs. This is where there is the most opportunity to vary the difficulty of the task to follow the needs of your Droid. Me Too is brilliant at sums and exchanging. It creeps me out he's so good. So, he clearly calculates his own sums and decides when exchanging needs to happen on his own. He usually figures out the chain of exchanges for multiple categories at the rug and we never see multiple product cards in a category on the working table. I'll have an "900" card on the table and send him off for a "200" card and he'll come back with three place values worth of cards because he has already summed the hundreds and understood the chain reaction of exchanges across several place values. If your Droid has trouble exchanging you'll want to have them bring the product cards for each layer of the multiplicand to the table and do each exchange one place value at a time. Often times the product card you need for a new layer is already on the table and the Droid needs to figure out why it's missing and find the sum of the existing card and the missing card so that the correct product card can be placed on the table. You don't have to say a word. They kids will find their own solutions. If your Droid is super young or super new to this your Brain can go ahead and tell them when to exchange or even what cards to exchange for what. It depends on your kids. Me Too's main problem on the large bead frame is realizing that something like "14 ten-thousands" is the same as "one hundred forty thousand." So, I've trained Kal-El when he is The Brain to always ask Me Too when he is The Droid for "14 ten-thousands" (just an example) so that Me Too has to figure out which cards that means. I've already seen a drastic improvement on the large bead frame as a result.
I don't know if Kal-El is as quick at the exchange chain as Me Too or not. I suspect not. As I said, Kal-El always wants to be the brain. I am perfectly happy to be the droid and, unlike Me Too, all I do is bring him things. When he plays with me, Kal-El has to find all the sums and exchanges and tell me what to bring. In essence, he is doing all the work except physically fetching things. That works out perfectly because that's the only part he doesn't like.
Me Too says that the Bank Game is easier than the large bead frame because there is less writing, you never have to cross out a decomposed multiplicand, and it is easier to split the zero(s) from the multiplier and move them to the decomposed multiplicand.