TimeTEX Subtraction Strip Board, in Wooden Frame "Montessori Premium"

The child uses the Subtraction Strip Board to practise the mathematical expressions in the subtraction tables 1-18

Understanding how to cross tens in subtraction tasks — the strip board for subtraction helps here. All subtractions that cross below the tens are practised.
First, we train on the 10. Once the tens transition has been understood, it works in the same way for any other tens such as 20, 30, 90 etc.

The natural wood strips, which correspond in length to squares 1-18, are used to indicate the number from which to subtract (minuend). The set of blue strips represents the subtrahend, which is the number to be subtracted.

A set of red strips is included for further exploration. A hardwood box is supplied for storing the red and blue strips as well as the natural-coloured strips.

Learning opportunities:

• learn about and practise subtraction
• learn to cross tens in subtraction problems
• create and practise inverse operations

Didactical information:

The teacher introduces both the blue and red strips. These are placed on the edges to the left and right, in order from largest to smallest. Once the value of the strips has been understood, the first calculation tasks can be set.
Here using the example of "7 - 4": The numbers 8 - 18 are covered with a strip of natural wood. Only the numbers 1 - 7 are still visible. Now the blue strip is placed flush on the right in the 7 field. The result 3 is now easy to read.

Variations:
Separate task cards can be used for extensive practice. Give the child 10 cards to solve one after the other. The problem to be solved should be written on the front, with the solution on the back.
Once the child is familiar with this method and has gained confidence, inversion tasks can be tackled. To do this, use the red strips to help you and start with an addition task beginning with the red strip: "4 + 5 = 9". The red strip is then removed and the result is 9 - 5 = 4. The children quickly understand the relationship between addition and subtraction.

Error checking:
You can see the result at the top when you lay the strips together. The solution can also be determined by creating a blue strip.

Strip board dimensions: approx. 43 x 33 cm
Large storage box dimensions: approx. 36 x 5.5 x 2.5 cm
Small storage box dimensions: approx. 20 cm x 6 cm x 2.5 cm
Wooden strip dimensions: each approx. 2 cm wide, length varies according to numerical value

Contents:

• 1 strip board (MDF) for subtraction in the wooden frame
• 1 storage box for the natural wooden strips made of beech wood
• 1 storage box for the coloured strips made of beech wood
• 9 red, 9 blue and 18 natural wood strips

Under the „Montessori Premium“ brand, we offer high-quality and excellently crafted Montessori materials that are very popular. If these products or parts thereof are made of wood, they are FSC-certified.