I created a diagnostic interview that I then conducted on two students in my fourth grade practicum. The purpose of the interview what kind of mathematical understandings each student had. I chose two students who had different abilities when it came to math so I could analyze what they already knew and where they should go next. This document includes the background information of the students, the actual interviews, their responses, and my analysis. As a teacher, I have to be aware of where all of my students are with their understandings so I can help each of them succeed.