FURTHER EXPLORATION USING BEAD BARS
b. Breaking Down the Addends
Aim: to give the concept of the dissociative property of addition
Materials: same as before
On a strip the teacher writes a combination of two or three numbers. The child constructs the problem with bead bars and symbols and computes the answer and puts out the corresponding bead bars for the sum, The child reads the equation.
Now try to do this one; the teacher lays out combinations in parentheses that equal each addend of the first problem, i.e. 1st 9+7+8= 24, 2nd (4+5) + (3+4) + (6+2) = The child computes this as before, adding the first two addends in parentheses, placing the bead bar for the sum below, etc. Those three are added again to obtain the same answer as before. It is noticed that the first and third equations are identical. In the second, each addend was broken down into two smaller addends.