Why is negative times negative a positive? What you didn't learn in school

Most of us just memorized this rule. But why is it actually true? And who discovered it? 0:00 intro 1:20 pattern 4:34 scaling 6:32 velocity 8:15 debts, discovery 10:55 textbook pattern https://math.stackexchange.com/questions/9933/why-is-negative-times-negative-positive scaling polymathematic https://www.youtube.com/watch?v=rpI78oh2liM https://www.desmos.com/calculator/rsqgblsqte velocity EpsilonDelta https://www.youtube.com/watch?v=4nG49xTTjIA dr sean https://www.youtube.com/watch?v=x_xxxvCJjBo debt https://hsm.stackexchange.com/questions/2631/historically-how-did-people-define-multiplication-for-negative-numbers https://www.reddit.com/r/askmath/comments/iernsb/why_does_multiplying_two_negative_numbers_make_a/ Brahmagupta discovery https://en.wikipedia.org/wiki/Brahmagupta quotes on negative https://www.meaningfulmaths.nt.edu.au/mmws/nz/sites/default/files/2021-02/babylonian-mathematics2-1.pdf https://nirajyadav.in/historical-quotes-on-negative-numbers-and-acceptance-by-brahmagupta/ other videos discovermath https://www.youtube.com/watch?v=qe_PnidC9IE Khan Academy https://www.youtube.com/watch?v=rK4sXm_MPWo Get early access to videos by supporting the channel https://www.youtube.com/channel/UCHnj59g7jezwTy5GeL8EA_g/join Patreon https://www.patreon.com/mindyourdecisions Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you purchase through these links, I may be compensated for purchases made on Amazon. As an Amazon Associate I earn from qualifying purchases. This does not affect the price you pay. Book ratings are from January 2025. My Books (worldwide links) https://mindyourdecisions.com/blog/my-books/#worldwide My Books (US links) Mind Your Decisions: Five Book Compilation https://amzn.to/2pbJ4wR A collection of 5 books: "The Joy of Game Theory" rated 4.2/5 stars on 564 reviews http://amzn.to/1uQvA20 "The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" rated 4.2/5 stars on 55 reviews http://amzn.to/1o3FaAg "40 Paradoxes in Logic, Probability, and Game Theory" rated 4.2/5 stars on 81 reviews http://amzn.to/1LOCI4U "The Best Mental Math Tricks" rated 4.3/5 stars on 148 reviews http://amzn.to/18maAdo "Multiply Numbers By Drawing Lines" rated 4.5/5 stars on 57 reviews http://amzn.to/XRm7M4 Mind Your Puzzles: Collection Of Volumes 1 To 3 https://amzn.to/2mMdrJr A collection of 3 books: "Math Puzzles Volume 1" rated 4.4/5 stars on 138 reviews http://amzn.to/1GhUUSH "Math Puzzles Volume 2" rated 4.2/5 stars on 45 reviews http://amzn.to/1NKbyCs "Math Puzzles Volume 3" rated 4.3/5 stars on 38 reviews http://amzn.to/1NKbGlp 2017 Shorty Awards Nominee. Mind Your Decisions was nominated in the STEM category (Science, Technology, Engineering, and Math) along with eventual winner Bill Nye; finalists Adam Savage, Dr. Sandra Lee, Simone Giertz, Tim Peake, Unbox Therapy; and other nominees Elon Musk, Gizmoslip, Hope Jahren, Life Noggin, and Nerdwriter. My Blog https://mindyourdecisions.com/blog/ Twitter https://twitter.com/preshtalwalkar Instagram https://www.instagram.com/preshtalwalkar/ Merch https://teespring.com/stores/mind-your-decisions Patreon https://www.patreon.com/mindyourdecisions Press https://mindyourdecisions.com/blog/press