What's in a Number?
From the desk of Melissa…
1%
What does that 1% mean? In my case, it’s…
-not the fat in my milk
-not my cashback rewards on my credit card
-not the effort I put into my work
-not the number of days over 100 degrees this summer
Unfortunately, it’s the percentile for my son’s weight! This number has caused a lot of concern around my house over the past few months. Our struggle with this situation has me thinking a lot about scale and proportion. What is the difference between 1% and 25% when you are talking about a 17 month old’s weight? It’s the difference between his needing to gain 1 pound or 5 pounds to catch up. For a 17 month old, that’s a big difference. Suddenly, 1% seems like a HUGE number to me.
This experience has made me realize how rarely we teach math in context. Because the real “value”, “size”, or “meaning” of a number changes based on where and how the number is used. That is why it is so important to teach students to attend to precision.
So what does this mean in the classroom? It certainly means that we use the correct number to quantify something and check our calculations for accuracy. It also means that we label our axis and intervals on our graphs. That we choose a scale for our data chart that depicts the information accurately. It includes understanding and using mathematical terms in their conversations and math journals.
Math is often referred to as the universal language but unless our students attend to precision based on the context of the real world problem they are solving, there is a communication breakdown! How can we foster this precision in our classrooms? Have your students help you create a rubric or checklist for a graph or data chart. Create math vocabulary word walls with student made illustrations and definitions. Make a wall of Non-Examples – a powerful experience for students to be able to label why something is inaccurate. (To see an example of the Frayer Model Non-Examples see the links listed at the West Virginia Department of Education. http://wvde.state.wv.us/strategybank/FrayerModel.html )
So what is in a number? A LOT! Students have to be able to name it, make sense of it in relation to other numbers and use it in a meaningful way. As you work to implement the common core standards for mathematics in your classroom keep in mind those standards for mathematical practice they are the WHY behind all of the content we are introducing students to.