Making change is an example of a missing part subtraction question, which our students tend to have difficulties with. One example might be:
Todd has $4.56 in one pocket. How much more does he have in the other pocket if he has $7.50 in total?
The question suggests two sets of money, one which is not given.
Subtraction by adding up works well with making change or finding a missing part money question.
For example, if trying to calculate the change when buying a 68¢ item from $1.00:
1 penny more makes 69¢, 1 penny more makes 70¢, one nickel makes 75¢, and a quarter makes $1.00. The total change is 2 pennies, a nickel and a quarter or 32¢.
This can also be tracked on an open number line or hundreds board.
|Adding up money on the hundreds board – smartboard file.This file is from D. Turner from Winnipeg.|
|Making Change on the hundreds board – smartboard file|