Order Really does matter

This week, we were wrapping up the first unit on Numeracy in Grade 9 and I asked the class this question: 7 + 3 (2 (4 +3) - 10(2 - 5) - 8). I wanted to ensure students followed proper BEDMAS and did not add the 7+3 before evaluating the brackets.

I posted the question on the board and asked each student to answer it individually. As I walked around the room, I noticed that every student had a different answer. So I put them into groups of three and asked them to go up to the board and solve the problem in their groups (without referring to what they individually did on paper). Surprisingly, I got three more different answers on the board:

As they solved the problem on the board, the discussion they were having in their groups about what to do first and what proper format should be was inspiring and showed their level of understanding. They started looking around the room at other groups work and one student asked "Is there only one answer to this?"

We talked about "would it be okay to have different answers". I asked "which answer would you want to get if the answer was your prize money?" and "which answer would you want to get if this was the number of steps you had to take?". We then summarized why it is important to have a set of rules to follow. It's not just a set of rules that your teacher is imposing on you, but absolutely required so that the correct answer (and unique answer) can be determined.

So what I had intended to do as a review of the unit ended up being a pretty rich conversation around order of operations and the real life need for them.