  Expressing physics problems in the form of a mathematical model is one of the
most important stages in the problem-solving process. Particularly in algebraic
symbolization, understanding the meanings of signs and being able to manipulate
them becomes a challenging task for students, especially when more than two
elements in the mathematical expression could carry a negative sign. We use
Conceptual Blending theory to investigate how students attribute emergent
meaning to the signs and how they articulate different signs in their algebraic
symbolization. The data for this research is drawn from oral exams of students
enrolled in upper-division physics. The results shed light on students'
understanding of algebraic symbols and their competence in formulating and
manipulating them.
