I made these mistakes, really just minutes ago, in attempting to solve a problem from brilliant.org.

my math mistake

 

Here was my written work:

IMG_2902

 

What was I thinking? What did I understand? What didn’t I understand? What questions would you ask to help me?

[Also, my ego does require me to announce that I got this problem on the third try. Maybe one of these days I’ll post something that I’m still stuck on.]

[Also also, do you like analyzing this sort of work? The problem is kind of tougher than what usually gets posted around here, so that I imagine that a lot of folks will skip this post once they don’t immediately see the answer to the question. But, hey, I’m curious to see what you all come up with. The advantage is that I can verify or disconfirm any theories that you might have about what the “student” was thinking.]