Addition Strip Board - First and second (commutative law) presentation. Montessori Math lesson

Addition Strip Board
Age 5 1/2 - 6
Prerequisite:
Addition Snake Game
• Addition Snake Game Mo...
Material: www.nienhuis.c...
A board divided into 18 squares horizontally and 12 squares vertically. Each square is 2 x 2 cm. Above the grid are the numbers 1 to 18, 1 to 10 in red and 11 to 18 in blue. A red line divides the board vertically after the 10.
2 sets of numbered strips - one blue set with numerals in red (1-9) at the end of each strip and one red set divided into squares by blue lines with numerals in blue (1-9) at the end of each strip.
Prepared addition booklet
Pencil
Addition Control Charts 1 & 2
First Presentation:
Chart 1
Invite the child
Introduce the activity and the material
Show him how to carry the board with the box with strip on top of the board
Have the child bring the board and the guide bring the writing tray with the addition table booklet, a pencil holder, a pencil, a ruler, a red color pencil
Introduce the board to the child, say: there are numbers on the top 1-18, this numbers we are going to find the sum. The numbers 1-10 are in red and 11-18 are in blue. There is a red line down the middle of the board after the 10, it is like or reminders the counter that we used in snake game to make 10
Take out the blue strips with the help from the ribbon and arrange them from 1 to 9 with the 1 touching the left side of the board. They have to be aligned on the left side
Take out the red strips and build them in the same manner on the right side of the board, on top of 11. They have to be aligned. Use a ruler to align.
Take out the addition table booklet and open to addition table 1
Point to the first equation and read the number: 1+1=
Ask the child: what is our first addend, the child will say one
Take the blue strip with the number 1 and place it on the first square of the left side of the grid
Ask the child: what is our second addend, the child reply: one
Take the red strip with number 1 and place it immediately to the right of the number 1 blue strip
Tell the child, we always find the sum in the number above the last square
Invite the child to read the number 2, he says: two
Invite him to write the number in the booklet
Remove the red strip, leave the blue strip in the square, show the child in the booklet the all number 1 so we need the blue strip to stay
Invite the child to read the next equation: 1+2 =
Take the red strip with the number 2 and invite him to read the sum and write it
When he has finish one page, show him how to check his work
Invite the child to bring control Chart 1 to the table and check the sum by comparing the booklet to the control chart
Second Presentation:
Essential Addition
Chart 2
Invite the child
Set up the table like the previous presentation
This time the guide brings grid paper and a protector (not the booklet), a ruler, a red pencil, a led pencil
Isolate three numbers on the board: 6, 7, 8.
Invite the child to choose one number, ex: the child choose 7
On top of the grid paper, write number 7
Tell the child, we are going to see how many ways to make 7
Choose a blue strip number 1 and place it in the first square of the board
Take the red strip number 1 and place it next to the blue strip number 1
Ask the child: does it make 7, the child will say No
Continue placing the following red strips ask the child: does it make 7? Until you reach the right equation. The child says yes
Write on top of the grid paper 1 + 6 = 7
Leave the strip on the board
Take the blue strip number 2 and place it on the board second row
Invite the child to find the correct equation, the child will find 5 to make 7
Write the equation 2 + 5 = 7
Continue in the same manner until you find all the possibility to make 7. Make sure to write each equation as you continue.
Isolate the last combination: the blue strip 6 and the red strip 1 by lower it to the bottom of the board
Ask the child: is there another combination that has 6 and 1 to make 7?
The child will say Yes the blue1 and the red 6 make 7
The guide say: they both make 7 so we do not have both equation written down
Take the ruler and the red pencil and say: Let’s cross the last equation
Remove the blue strip 6 and red 1 and place them back on the table
Do the same process with the rest of the strips equations (5 and 2, 4 and 3). This law is called commutative law.
When finish
Invite the child to bring control chart 2 which contain the essential combination that he needs to memorize to verify his work
Show the child Put away the strips. Put the ribbon (the ribbon is only for the 9 blue strip) in the box start with the blue strip 9, leave the ribbon with your finger, continue with the other strips. After the blue strips, start with the red strip 9 on the opposite side. Close the box
Bring the materials to the shelf
Purpose:
To give the child all the possible combination 1 - 9
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