The adventures of a fourth grade teacher in East Central Illinois.

Real-Life Applications of Fourth Grade Math

Over Spring Break, I had an opportunity to chat with a friend of mine about what is taught in fourth grade, particularly in math. He is in a railroad engineering program, and has to use fairly advanced math on a regular basis for his work.

But then he pointed out that he only uses advanced math for his rather technical work. When it comes to day-to-day activities, the type of math he uses, if he uses math at all, is essentially what I teach my students: addition, subtraction, basic multiplication, division, fractions, and simple probability.

So, of course, I decided to use this as the springboard for math instruction today. Because, you know, having an engineer admit that the math he learned in fourth grade is what he uses most often is much more impressive to my students than to hear it from their teacher.

I have two math groups in my class. I told the first group about this, and then transitioned into a story about my wife and I eating some red velvet cake over the weekend. I explained that I made a cake, cut it into twelve pieces, and then had to leave for a few hours. While I was gone, my wife at a fourth of the cake. When I got home, I ate a third of what was remaining. I asked them to figure out how many pieces of cake we each ate.

With the other group, I talked about planning a trip to Kansas City, Missouri, to visit my oldest brother and his family at some point. I explained that it will take about six hours to drive there, and we need to figure out how much gas we will need to get there. I told them that we know the trip to Washington, Illinois, where my parents live, takes about an hour and a half by car. So I asked them to figure out how many times longer the dive to Kansas City would be. Then I said that we use about three gallons of gas to get to Washington, so I need to figure out how much gas it would take to get Kansas City. I wrapped up with pointing out that gas currently costs $3.96 per gallon, but we should just round up the number to figure out about how much gas we’ll need for the round trip.

After each group figured out the answers to these problems, I reinforced the point that this is the kind of math adults use every day; the same kind of math that they are learning right now in class. Of course, that doesn’t mean advanced math doesn’t have its uses. People definitely do use calculus for some types of work. But when it comes to daily activities, most of us aren’t going to break out the quadratic equation when figuring out how much gas will cost for a trip.

That didn’t stop me from quickly throwing the equation up on the board, just to show them what it is. After all, my high school calculus teacher, Mr. Charles “Chuck” Brunner, spent an awful lot of time helping me and my friends learn it. And now, ten years later, I still remember it: x equals opposite of b plus or minus the square root of b squared minus 4ac all over 2a.


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