The Number Line Model
The use of Number Line model helps children to identify and answer addition or subtraction easily. This is because by using this model, the children are able to locate whether the arrow is pointing to the right (positive or increasing value) or to the left (negative or decreasing value).
For example, the picture below portrays the equation 5 + 4 = 9. As the added number which is 4 is a positive value, so the arrow will move four steps to the right side of 5.
This model is also applicable for subtraction where the arrow will move to the back to indicate the decreasing value. For example: 5 – 4 = 1. The arrow will move four steps to the left of 5 (National Council of Teachers of Mathematics, 2011).
The Stack or Row Model
This model uses objects or rows that are lined horizontally or vertically so that children can see clearly the difference of the amount of the objects after being added or subtracted. For example, in the picture below, children can see the difference in length of the row for number one until ten.
For example: 5 – 3 = 2. Children are able to identify the difference in the amount and length of row for this equation.
