In this lesson, addition is defined as putting numbers together. Addition is indicated by the use of a plus sign. To represent the concept of addition, two numbers are shown that are to be added. Objects are shown to represent each number. Addition is defined as counting all the objects.
Addition is represented as a number sentence. A number sentence is defined as a statement that two numbers are equal. Numbers that are equal are the same number, but they may be written differently.
In this lesson, students learn to add two numbers by counting on from the larger number. They start counting from the number after the larger number, and count a number of times equal to the smaller number. In this lesson, they keep track of how many times they counted by clicking to add objects above the smaller number in the addition sentence.
In the lesson before, students learned to add by counting on from the larger number when they have blocks to keep track of how many times they have counted on. In this lesson they use that knowledge to count on to add when they don’t have blocks to keep track of their counting.