Research findings show the difficulties younger students have in working with graphs. Higher mental operations are necessary for a skilled interpretation of abstract representations. We suggest connecting a concrete representation of the modeled problem with the related graph. The idea is to illustrate essential mental operations externally. This is called supplantation. We provide this special kind of support in a multimedia learning environment using several computer-specific features. Based on an information-processing model we identify two different types of supplantation of mental operations on graphs: first, supplantation of how to relate a certain point of the graph to the underlying concrete object or situation. Second, supplantation of how a point of the graph and the underlying fact or situation co-vary. In an empirical study, combinations of these types were investigated. The results indicate that such a supplantation of mental operations on graphs can become a useful tool to support adequate understanding of graphs. However, supplantation should be adjusted to individual abilities.