The TORA, Solver, and AMPL materials have been deliberately compartmentalized either in separate sections or under the subheadings TORA/Solver/AMPL moment to minimize disruptions in the main text. Nevertheless, you are encouraged to work end-of-section problems on the computer. The reason is that, at times, a model may look “correct” until you try to obtain a solution, and only then will you discover that the formulation needs modifications.