In my role as a PD Coordinator for Charlotte-Mecklenburg Schools and also as an outside consultant in other districts, I get many opportunities to observe classes. I see episodes of great teaching and I routinely share strategies with other teachers from strategies I observed in action. But in one seventh grade math class I recently visited (pre-EOC review), the teacher had this problem on the SmartBoard for her kids to solve:
Johnny went bowling and had the following scores for his games: 100, 150, 200, 300. Find the LCM (Least Common Multiple) of his scores.
What? The LCM of his bowling scores? This problem may have been an attempt on the teacher’s part to provide a real-world context – instead of a question that simply asked students to find the LCM of 100, 150, 200, and 300. This would have been a perfectly fine problem. But the context she offered seemed to me to be grossly inauthentic for at least three reasons.
First, nobody is named “Johnny” anymore (Ok, it’s a pet peeve of mine when teachers refer to the typical or representative kid as “Johnny.”).
Second, who bowls a 100 (a crappy score) and then bowls a perfect game (300) just three games later?
Third, and most importantly, who ever calculates the LCM of their bowling scores? This is a totally useless calculation in this context. The LCM, 600, means nothing in the context of bowling scores. I could see if she asked kids to find the mean of the four scores, but the LCM?!
How can we expect kids to see the usefulness and purpose of the math concepts we teach them when we offer such lame examples? It’s not as if the LCM of a set of numbers doesn’t have authentic applications in the real world (e.g., in digital music tracking when repeating sequences are played together but vary in bar length).
Is it that the teacher didn’t really understand the value of finding LCMs or what LCMs really mean? I don’t know.
What I do know is that if we’re going to bother assigning a real-world context to a math calculation we’re asking kids to perform, we ought to make it a little more realistic. Our students’ value, respect, and sense of purpose of what they’re learning is in the balance. dven.
