Teaching Absolute Value
I use the warm up above when teaching Absolute Value in my Algebra 2 course. It bothers me that many students define absolute value as “always positive.” My next question to them is always “Why is it always positive?” That’s a question you will find on my assessments as well. I want the key word to be distance for students when they think of absolute value. I want them to understand signs of positive and negative as describing direction. And those distances and directions are from zero (a pretty intuitive starting place for students in “the middle” of our number line).
I put together a few questions that hopefully lead students to think about absolute value in this way. The two questions at the bottom of the first page help identify 2 different situations: one where direction matters and one where direction does not matter. On the second page, I try to emphasize the idea of more than one possible solution. When the direction is not given or specified, there can be many possible solutions. These questions usually lead to some great conversations. It’s also nice to reference these questions later by asking students to remember how many directions Bart could skateboard or Otto could drive. By talking about concepts in everyday situations without the distractions of notation, students can get a firm grasp of the concept before diving into problems where they will just try and memorize steps.