MIT’s Street Fighting Mathematics course from MIT’s January IAP 2008 session is all about getting quick, rough answers without diving into full proofs or long computations. Instructors Scott Aaronson, J. Michael Steele and Steven G. Johnson guide you through techniques like dimensional analysis, bounding arguments and perturbation methods. Want to estimate how long a football field’s worth of sand weighs? You’d start by breaking down volume into length, width, depth, assigning rough densities, then multiplying—no precise integrals needed. One standout chapter shows you how to turn a nasty sum or integral into something manageable: pick a simpler function that lies above or below your target, integrate that instead, and you immediately pin down useful bounds. Elsewhere, they tackle random walks with hand-waving arguments that nevertheless nail the √N law for displacement, or derive Stirling’s formula by matching areas under curves rather than invoking complex gamma-function machinery. Each example pairs a physical intuition with the barest algebra. The readings also include a section on scaling laws—how changing one parameter by a factor of ten might affect your result by factors of a tenth, a hundred, or something in between. You learn to identify which terms in an equation dominate at large or small limits, then drop the rest. By the end, you’ve built a mental toolkit: before crunching numbers, you guess the order of magnitude, check a quick plot or two, then refine if needed. It trains you to trust your gut—but only after you’ve turned that gut feeling into a systematic shortcut. Finally, the course isn’t confined to physics. There’s a module on applying these heuristics to algorithms: how to estimate run time or memory use when you barely have an hour before a deadline. That section shows you how to turn O(N²) into O(N log N) in your head by spotting which loops or recursive calls really matter. It’s a crash-course in intellectual triage—finding the heart of a problem, tossing the rest aside, and moving on faster.