When a professional engineer solves a mathematical problem using technology, he/she generally uses a single one-step "high-level" command of a readily available computer package to obtain the solution immediately. This should not happen during his/her learning cursus. In an engineering mathematics course, the educator should decompose the solution process into elementary steps and reinforce each step by a "low-level" usage of a CAS. This approach is absolutely essential in order to provide the future engineer with the conceptual insight into the solution process. We illustrate this with the teaching of the solution of ordinary differential equations using Laplace transforms.