The base ten system can be used by the mathematics educators and teachers to build effective models for addition that allow students to recognize the importance of adding ones to ones, tens to tens, hundreds to hundreds and so on. The strategy used to add multi-digit whole numbers is as following: add the ones and regroup as necessary to get ten and ones, add the tens and regroup as necessary to get hundred and tens, add the hundreds and regroup as necessary to get thousand and hundreds and so on….
The dynamic model built relates to the concept of base ten blocks using 2D model: equal rectangles representing ones, the strip (block) of 10 rectangles representing tens. While is proceeded with the algorithm regrouping occurs as needed.
The model of this case and the respective procedure serve as a demonstrative model for the teachers to use in their classroom, equipped with computers, or in computer laboratories. By watching this case the students are able to figure out and build in their minds similar models for other cases of adding/subtracting multi-digit numbers.
