The question was about the range of a set of temperature numbers, the difference between the high value and low value. To get this number, a student needs to subtract the low value from the high value. This would seem straightforward. Nevertheless, I stepped right into a trap I’ve hit before.
Student: How do I get the answer to this problem?
Me: It’s the range. What’s the difference between the high value and the low value?
Student: The high value is hot. The low value is cold.
Eduhonesty: Sigh. True enough. I agreed that 101 degrees was hot and 45 was pretty cold. Then I started to teach the math I have taught — how many times? — in the last few weeks. Fortunately, I have learned to be persistence personified. I do not give up.
Does my student have the idea of mathematical range now? If not, we’ll do it again.