At City & Country School the 3rd graders run the school post office and the 4th graders run the school store. With all this retail responsibility our kids need to know how to make change, and I have developed a system that is easy to implement and incredibly effective. The system is concrete, and kids are relieved that they do not need paper and pencil to quickly and accurately figure the correct change in a retail context.
Making change--especially under the pressure of a waiting customer--is a considerable challenge for most children. This is in large part due to the fact that most teachers encourage using subtraction to calculate the change, rather than the counting-on method, which is far more effective and easier to learn if taught correctly. If you patronize any retail business that uses an old cash register (that does not calculate the change), you will notice the cashier doesn't use subtraction, but rather counts on from the purchase price to the amount given by the customer. That is, if the cost is $12.78 and you handed over a twenty dollar bill, the cashier will hand you some coins and say 'That's 13' then hand you 2 dollars and say 'that's 15' then a five dollar bill and say 'and 5 makes 20.' This is the most efficient way to calculate change and kids can easily become adept quickly by following my very systematic approach. I find most third and fourth graders become quite adept at making change after five key activities. If you have math every day a week should do it!
This product contains four worksheets, one for each phase of the process, plus a full description of the concepts behind the approach and how to teach them. The approach works because it is concrete; that is, students are actually using the money in their hands as a guide, rather than relying on paper-pencil calculations. It's a very simple process that you will fully understand after one quick ready of my two-page description. I promise you will save yourself and the children a great deal of aggravation with this normally tricky concept.