Subtraction Snake Game MONTESSORI Mathematic Lesson - Association Montessori Internationale version

Prerequisite:
Snake Game Addition
Direct Purpose:
To help the child memorize the basic combination of subtraction
To demonstrate that subtraction is opposite to addition
Age:
5 1/2 , 6
Material: www.nienhuis.c...
25 gold bead bars in a gold box
5 colored bead stairs in a green box
5 gray bead bars in a gray box
1 black and white bead stair in a black and white box
A tray
A felt mat
A counter or bridge
First Presentation: AMI (Association Montessori Internationale ) version
Invite the child
Introduce the activity and the material
Show the child how to carry the materials and the guide can bring the felt mat
Bring the material to the table and sit down
Unroll the mat
Show the child the gold bead bar and place it left side of the tray
Keep the gold box open
Open and take out the black beads and place the box right side
Keep the black box open
Open the gray box, take out the gray beads to the felt and introduce the beads. Introduce The first nine bead bar, take one of each. Say: This is similar to black and white bead white bar. Say: show the first five are light gray and the rest of the beads darker gray so it is easier to count.
Take 1 to 9 gray beads bar on the mat
Close the gray box and place it on the tray
Invite the child to build inverted triangle the black and white beads
Take the counter out
Take out the color bead bars, make sure you take an amount equal to or greater than the grey bead bar so you will not have negative numbers when subtracting
Close the gran box
Say: I will be making a snake like we did in addition snake game but this time i am going to alternate the color bead bars and grey bead bar
Start making the snake using three of four color beads at the beginning so you will not have negative when subtracting. Tell the child about this
Continue by placing mix color bead bars and grey bead bars
When you place the grey bead bar, place it such a way so it is easy to count: position the darker color to the left.
Start doing it and say: this time we have more rule
Remind the child other rule:
We are going to count to ten, every time we make ten, we need to exchange to a ten golden bead bar.
We always start counting after the last golden bead bar.
Tell the new rule: And this time when we get to a grey bead bar, we have to take away the amount of bead that are the same as the grey bead bar but we can only take away from the golden bead bar or from the black white bars NEVER from the color bead bars
Start counting as the same was as in the addition snake game, make necessary exchange of ten color beads for a golden bead bar.
When you get to the grey bead bar, ask: can we keep counting? the child say : no
Then ask: So what we have to do? He will tell the rule or you say the rule: Whenever we get to grey bead bar, we have to subtract
Count the grey bead bar backward (right to left)
Take away black white bead and golden bead that correspond to the grey beads
Ask: How many we have after the counter?
Replace the extra after the counter with the black white bead bar
Return the golden bead bar to the gold box and color bead in the black box. Black white beads back to the inverted triangle
Continue counting for the rest of the snake
Depending on the ratio the color beads and the guy beads, the result would be nothing on the table
If there is color beads remaining, it means we have mistakes
If the child makes mistakes, he has to do all over again. Say: next time you have to take more color beads
Do the control of error 1
When the child finish, have him to put the material away
Note:
Put 3 or 4 color beads at the beginning so it won’t be a negative results.
Direct Purpose:
To help the child memorize the basic combination of subtraction
To demonstrate that subtraction is opposite to addition
Age:
5 1/2 , 6