Array Addition Strip Board Montessori Math
Adrian 3 years Adrian 42 months (3.5 years old) MATH 🔢

Addition Strip Board (Montessori Math Lesson)

Montessori Addition Strip Board teaches preschoolers and kindergartners the mathematical concept of adding numerals one through nine more abstractly.

A traditional Montessori material: Addition Strip Board (buy here), introduces a child to adding numbers a little bit more abstractly. This material should be presented to a child who has a very strong understanding of quantity to a numeral concept because here there is no tangible quantity like spindles (buy here) or golden beads (buy here) from Teens Board (buy here) in previous lessons. Still, this is a great way to introduce a child to the concept of combining numbers, to make new numbers. 


HOW TO set up the Addition Strip Board:

Blue control rods without the lines should be positioned to the left of the board, and the red rods that you will be adding (addends) to the right. (I know it is counterintuitive.) In this lesson, we are using equations. You can use wooden numerals (similar here) or you can simply write equations on a paper and cut them out (lamination is optional).

Addition Strip Board prepares a child for abstract mathematics by offering concrete experience in addition of numerals, as well as aiding in learning addition tables. Most importantly, this lesson exposes a child to the world of numbers, which is very exciting and intriguing, so to keep the interest alive, stop the lesson before the child’s interest starts to wane. Usually, you will do three equations at a time, but if the child wants to do just one, it is totally fine: merely return to this material at a later point – solve as many equations as the child shows interest in. 

PRESENTATION of this Montessori Math Lesson:

For example, the equation 6+4 =10. First, the child will line the blue six rod under red top numbers. Then, the child would find the red four rod and place it right next to the blue on. Besides, you can reinforce the resulted sum by counting squares underneath and/or confirming the sum by pointing to the number above. Once the equation is solved, a child should place the rods back to the sides of the board before proceeding to the next equation. 

Simple Addition and Making 10s (Montessori Addition Strip Board Math Lesson) from Anya on Vimeo.

It is very important to have this material set up orderly to ensure success and prevent frustration. When the inner need which compelled the child to perform this activity has been satisfied, the material should be put back into the box. The best way to put this back is to start with the longest rod because there is only one way it will fit back in the box. Lastly, place the material back on the shelf.

DIY Note: Addition strips can be easily made by cutting red and blue strips of heavy cardstock. 

After solving this equation, Adrian wrote it down on his worksheet. You can also emphasize that sum equation has a commutative property: meaning that changing the order of the operands does not change the result [6+4=4+6].  See the above video’s post here where I also linked a free download of Math Addition work-sheet Adrian is writing on.

For more on addition, see a post here “Montessori Math Simple Addition using Marble-Counters” which also has an intro What is Montessori Math? Also, see here an Extension to Strip Board: “Addition Strip Board Making 10’s.”

Recycled Dot Stickers DIY Making 10 s


Do you have leftover sheets from dot stickers? Well, put them to use with this super easy DIY making 10s activity. Simply cut a rectangle of ten used-up stickers (it is two rows of five), peel of the back and adhere to a white paper. Now, offer your child to fill the ten-dot-rectangle with different combinations of two colors of stickers making ten. We are also using a traditional Montessori Addition Strip Board to reinforce the understanding of addends~ any of the numbers that are added together ~making a sum of ten. I also introduced the term “commutative” ~ meaning that the addends can “commute” ~ travel switching sides, and the sum, will not change. Please, emphasize that commutative property ~ in mathematics, a binary operation is commutative if changing the order of the operands does not change the result ~  applies to addition and not subtraction. We are also referring to 1 2 3 Count with Me (Trace-and-Flip Fun!), which an amazing book to teach your child proper number tracing!

For more on math, see here a post video “Beginning Subtraction.”

See links to previous math lessons here.

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  • Reply Kimberly Cumberbatch May 25, 2020 at 10:51 pm

    Hi Anya
    Curious! Why does the board only goes up to 18 and not 20?

    • Reply Anya May 27, 2020 at 3:14 am

      Hi Kimberly, if they can work with 2 digit numbers up to 20, then they can work with any numbers. (Just to think, we only have 10 numbers!) So, once they master the skill with the board and after that they work with place value and cubes and hundred squares, they can move to dynamic addition. Xo

    • Reply Anya ♡ Montessori From The Heart January 18, 2022 at 7:25 pm

      Actually, the largest addends are 9 and 9. 9+19 is 18, so that’s why the board only goes till 18.


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