I found a similar question asked about a decade ago in the English stack exchange, but there were no definitive answers, so I hope this is ok to ask here, where people may have more relevant experience.
When writing, what is the correct verb form for a modulo function?
For example: "function f(x) takes a logarithm of base 5, multiplies by 2, adds 3, subtracts 5, and…. modulos by 9(???)"; or "we then modulo 10 by 5"
The best I can come up with is "performs a modulo function with quotient 9", but I don't know if that's correct, and it sounds like there should be a simpler word or phrase.
Best Answer
I might say "reduce mod 5" or "take the remainder mod 5", and to be clearest, I'd specify the output range of the reduction operation, e.g. "reduce mod 5 into $\{0,...,4\}$".
It's a common misconception that the "mod" notation in math primarily signifies this reduction operation. Often, it just describes the equivalence relation (modular congruence) that holds between any two integers that differ by a multiple of the modulus. E.g. $28\equiv38\pmod{10}$ and $28\equiv8\pmod{10}$ are both true. (See this answer for more on the two usages.)