sources:

History of mathematical notation - Wikipedia

Floor and ceil: https://twitter.com/fermatslibrary/status/1530589088180494336

equals =: https://www.caltech.edu/about/news/question-week-who-invented-equal-sign-and-why-171

arithmetic symbols: https://www.scienceabc.com/pure-sciences/start-using-math-symbols.html#:~:text=The %2B symbol is derived from,addition during the 14th century.

symbols of calculus: https://mathshistory.st-andrews.ac.uk/Miller/mathsym/calculus/#:~:text=The first appearance of the,indicate the integral of x.

modern algebra notation: https://sites.math.rutgers.edu/~cherlin/History/Papers2002/vieta.html

vector notation: https://en.wikipedia.org/wiki/Vector_notation