Formative Assessment 139

Assessment Problem: 

3( x + 2) = 12
x + 2 = 4
a) What step did the student use to get from the first line to the second line?
b)  Do you think that this way of starting this problem is (a) a very good way; (b) OK to do, but not a very good way; (c) not OK to do?
c)  Explain your reasoning

Mathematical Issues: 

This task assesses students' ability to solve equations using non-conventional methods.

Algebraic Relations
Common Core Standards: 
The Cover-Up app also demonstrates the value of informal procedures in solving equations.
Research References: 
Rittle-Johnson, B., & Star, J. R. (2007).