Base 10 Addition:

Two Place Addition

Three Place Addition

The purpose of this model is to teach and explain the base 10 addition procedure. When the models are run a random addition problem of the corresponding size is presented in the standard form together with a model consisting of quantities of balls, color coded by place value, for the digits of the summands. The steps of the procedure are carried out by clicking on the “+” button which changes color for the different place values. As the digits are added the balls for the corresponding place value drop into a collector with a counter showing the total. If the total reaches 10, the 10 balls are replaced with a ball which is moved to a “carry” holder for the next place value.