To better facilitate academic instruction to students throughout a lesson, teachers must monitor student understanding of the material, and adjust the instruction methods as necessary. When students fail to understand material, it is essential for the teacher to re-teach content, and possibly work with students individually until they comprehend instructional content. While teaching mathematics during my advanced student teaching, I came across a small group of students who found it difficult to grasp the concepts of a particular lesson. I was teaching a lesson on oblique and acute angles (oblique are greater than 90 degrees, while acute are less than 90 degrees). After explaining the concepts and providing visual examples, I had the students create their own oblique and acute angles using geoboards. Most students in the class grasped the concepts easily and could produce the angles on the geoboards with rubber bands. However, I found one student who continued to struggle with each technique presented. I worked with the student individually and had her look at the clock to help her understand the two types of angles. With this particular case, I found that only ten minutes of one-on-one instruction made all the difference in her understanding of the material. I realize that had I not taken the time to work with this student, she probably would have fallen behind, thus eventually finding difficulty with future concepts. This is why I feel that constant assessment of student understanding of instruction is essential.