January 1, 2026
Math with gloves off
Street-Fighting Mathematics (2008)
MIT drops free “Street‑Fighting Math” and the comments start swinging
TLDR: MIT Press released “Street‑Fighting Mathematics” free, a guide to quick, intuitive problem‑solving. Commenters are split between praising its approachable, old‑school insight and saying modern engineers just crunch numbers, with jokes about actual street fights and shoutouts to a popular successor course.
MIT Press just made Sanjoy Mahajan’s “Street‑Fighting Mathematics” free, and the community treated it like a punchy comeback album. Fans call it the antidote to boring school math, with one commenter praising “great improvements in insight and simplicity” while throwing shade at the US classroom baseline. A link hero swooped in with the direct PDF, and the thread turned into a mini pep rally for quick, intuitive problem‑solving: think eyeballing extremes, drawing pictures, and simplifying messy problems until they tap out.
Cue the jokes: someone asked if it teaches “how to distribute fighters” to win battles, and honestly, with chapters like “Picture proofs” and “Singing logarithms,” the title kind of invites it. But not everyone’s ready to spar—an engineer admitted they’d still “go straight to numerical methods” on the job, which lit up the classic Reddit debate: is fast-and-loose math a superpower or a cute hobby? Meanwhile, a crowd plugged the spiritual sequel, MIT’s “Art of Insight” course, for those craving more tactical brain training.
Verdict: half the thread wants to revive old‑school intuition, the other half fires up spreadsheets, and everyone’s downloading. The math may be rough‑and‑ready—but the comments are pure cage match.
Key Points
- •The course outlines session-by-session topics and post-lecture readings for Street-Fighting Mathematics.
- •Sanjoy Mahajan’s textbook (MIT Press, 2010; ISBN 9780262514293) is the core resource and is available as a free PDF.
- •An earlier edition of the textbook, title page and table of contents, and references are provided as separate PDFs.
- •Sessions cover methods such as dimensions, extreme cases, discretization, picture proofs, and taking out the big part.
- •Applied sessions include drag, pendulum period, operators, and a handout on approximating logarithms via musical intervals.