Mathematische Schülerbücherei some questions

[Felix Gross]

That site is awesome for a number of reasons, even calculator related reasons.

One is that it contains PDF Files for a math encyclopedia (in German, https://mathematikalpha.de/lexikon ) which I still find very useful. I have a pdf file of this on my smartphone. The book gives you not only the equations but also examples and lot of graphs to learn or re-learn some higher math material fast. The color scheme is a bit intense but actually rather logical. The "how to use a slide rule" is bonus material... The book originated in the sixties.

The book was published in English as "The VNR Concise Encyclopedia of Mathematics" which you can find on the net. I remember a glowing review of this in the PPC Journal and to my knowledge EduCalc sold it.

Mr. Polster does care about the copyrights of the authors. So the material he publishes is legal. He took the pains to ask the rights holders and in almost all cases he got it.

The site offers complete math, chemistry, physics and astronomy (!) high school texts from former East Germany. The content gets quite advanced when you check out the grade 12 books, the last year of East German high school. They introduced calculators formally into the text much earlier than in my part of then West Germany. Also interesting to compare with today's' math texts which adhere to very different paradigm. No idea if that is good or bad, but it is different.

Even if your German is minimal or non-existent, you will catch the drift when you look at those books

Felix