In this article the authors analyze the written solutions of some first year undergraduate mathematics students from Victorian universities as they answered tutorial exercise questions relating to complex numbers and differentiation. These students had studied at least Mathematics Methods or its equivalent at secondary school. Complex numbers was a new topic for some students. The focus in these examples is on the extent to which students display an awareness of structure in complex number and algebraic expressions. The authors assert that structure sense includes an awareness of structure in numeric as well as in algebraic expressions. They emphasize that the lack of structure awareness reported here was not observed with all students--there were obviously many students who had a sound grasp of numeric and algebraic structure. However their observations suggest that there are also many students for whom this is not the case.