The positive correlation between spatial ability and mathematical ability has been well-documented, but not well-understood. Examining student work in spatial situations that require numerical operations provides us with insight into this elusive connection. Drawing on student work with angle, length, volume, and area, we examine the ways in which students associate numerical operations with their spatial structurings of objects. We find that for students to correctly coordinate their spatial structurings and numerical operations, their solution methods must satisfy basic properties of measurement functions. We illustrate this claim by providing examples in which students successfully and unsuccessfully employ spatial-numerical linked structurings. [For complete proceedings, see ED581294.]