On: I liked this simple calculus exercise

[eesmith]

And introduced by Iverson for APL in 1962: https://www.johndcook.com/blog/2021/04/15/floor-ceiling-brac... and https://en.wikipedia.org/wiki/Floor_and_ceiling_functions .

[hgsgm → eesmith]

APL, famous for baffling programmers with weird notation, also known for making one part of math more readable :-)