Classroom Discussion

Problem Solving Talk Points

Equation: Teacher example

[-(x+4)]/2= -8

2 x [[-(x+4)]/2] = -8 x 2

-(x+4) = -16

[-(x+4)]/-1 = -16/-1

x+4 = 16

(x+4) -4 = 16-4

x= 12

Common student error

[-(x+4)]/2= -8

[[-(x+4)]/2] -4 = -8-4

How did you decide what to do first?

Common student error

[-(x+4)]/-1 = -16/-1

-x-4= 16

Did you figure out that didn’t work? How did you figure out this wasn’t going to work?

common student error

(x+4) -4 = 16-4

x= 10

What did you do that helped you make sense of this problem?

10+4 =16

This incorrect statement helps make sense of the incorrect method.

16-4 =12

12+4=16