Heuristic
Heuristics can be used to estimate an answer which is then made more clear by performing an exact solution at a very small scale, perhaps to save time, money or labor on a project - for example a heuristic guess as to how much weight a bridge is expected to carry can be used to determine whether the bridge should be made of wood, stone or steel, and appropriate quantities of the needed material can be purchased while the exact design of the bridge is being completed.