We learned that when calculating change, we must, must, must subtract. We had so much fun dramatizing what happens when you add to give change, that I used my two volunteers in this very important Public Service Announcement.
I am hoping that after today's very memorable and hilarious lesson about the importance of subtracting in order to calculate change, no one will ever find them in a real-life or testing situation where they confuse what they are to do.
The gasps that came from our audience (my class) when they realized that by adding instead of subtracting when calculating change, you are essentially giving the customer the item they bought, the money they gave you PLUS the cost of the item! Perhaps today was also a bit of a business lesson!
This lesson really wasn't about making a video, but about dramatizing the reality of what happens when we use the wrong operation in Math. My hope is that in doing these types of memorable and funny activities, children can measure the reasonableness of their own answers and be able to judge on their own if they are on track or not. It's all about becoming an independent Math thinker.
For us grown-ups, we get it because we can apply that logic that tells us, "No, I just bought an item, the change I get back should not exceed the cost of the item or the money I gave the clerk". Kids don't know this and it's important to provide crystal clear(and hopefully funny) examples of why we must subtract. While the video is a little out of context within the confines of this blog posting, my hope is that parents and blog visitors will see how critical it is to make Math fun and memorable. A few minutes of silly goes a long way in a child's learning.