Categories Complex Numbers N.CN.2 Adding Complex Numbers Post author By mpershan Post date August 20, 2012 3 Comments on Adding Complex Numbers What is it about complex numbers that this student finds confusing? Do you think he would make an identical mistake on ? Why or why not? Share this:EmailPrint ← Call for feedback: Categories → Conceptual Understanding of Line of Best Fit 3 replies on “Adding Complex Numbers” in a sense there is an ‘order of operations’ error/overapplication of associative property here, where the student is working with (12+3) before addressing the “attached” i, and similarly with (2-3). In that case, I wouldn’t be surprised if the mistake was repeated to treat (12+3x) as (12+3)x. It would be interesting to give the student the same problem with x’s and see how they responded, but I’m also not totally sure about the distinction they would then make – i is not really a variable or an unknown, so if you addressed their error here by telling them to treat i like x, I expect in the next round you’d get 12+3i (=0), 3i = -12, i = -4. Why don’t we just write complex numbers as bi+a? This would fix the whole problem, I am sure. Teach complex numbers through geometry first. Comments are closed.