# On Average Jun 2022

Most everyone in math knows these tricks — here’s a summary of techniques used to make quick mental calculations using averages. In school, I have 8 exam scores; what’s my average? 90 92 88 95 97 81 85 100 ~~~ Guess maybe 90, then mentally calculate the running residual sum using two or three numbers […]

# Lucky Me Jun 2022

Growing Up At our house: We had newspapers, a couple magazines (*), a few religious books, and a set of World Book [encyclopedias]. My brother and I read the hell out of those encyclopedias. I say this broadened our interests but I also say we developed our innate interests. We all made [regular trips to […]

# Lecture by Richard Feynman – with transcript Feb 2022

Richard Feynman Lecture “Los Alamos From Below” Transcript of lecture at UCSB in 1975 Lecture Transcript Transcript Overview Los Alamos From Below: Reminiscences 1943-1945, by Richard Feynman Length of Interview: 01:18

# Long Division — Just Write the Answer Oct 2021

Five Easy Inverses (marked) What is 44/201? (marked) Hey Wolfram Alpha, what is 44/201? Five Easy Inverses (unmarked) What is 44/201? (unmarked) References Dr. Aitken was both a mathematician and a mental calculator. His prowess is described in the first link below (about halfway down the page). https://mathshistory.st-andrews.ac.uk/HistTopics/Mental_arithmetic/ And here’s a second link — well […]

# Long Division Simplified Oct 2021

Problem 1 Problem 2 References Dr. Aitken was both a mathematician and a mental calculator. His prowess is described in the first link below (about halfway down the page). https://mathshistory.st-andrews.ac.uk/HistTopics/Mental_arithmetic/ And here’s a second link — well worth reading. https://cowles.yale.edu/sites/default/files/files/pub/d17/d1750.pdf

# Mathpix Snip Sep 2021

Take a photo of a handwritten math problem and get the LaTeX code from your smartphone (or computer) Take a photo on the iPhone, and crop it. Submit and voilá. Here’s the LaTeX code (I added code shown in red to remove the equation number): $$$\therefore R_{1}=\left(\frac{q a}{2}\right)\left[2-\alpha^{2}(1+\beta)\right]$$$