When I left off yesterday, I pointed out a certain kind of algebra expression that tends to lead students to make mistakes. It was an expression like this:
8 – 2(3x – 7)
I pointed out that students often mistakenly combine the 8 and the 2, to get this:
= 6(3x – 7)
= 18x – 42
The theme of these posts is: how to help students avoid mistakes in algebra.