Formative Assessment 87

Assessment Problem: 

Mary has the following problem to solve: “Find value(s) for x in the expression: x + x + x = 12” She answered in the following manner.
a. 2, 5, 5
b. 10, 1, 1
c. 4, 4, 4
Which of her answer(s) is (are) correct? (Circle the letter(s) that are correct: a,b,c)
State the reason for your selection.

Mathematical Issues: 

Discusses the concept that the variable x must be the same value at the same time within the context of a particular problem.

Variables & Expressions
Research References: 
Fujii (2003)