Where does “arithmetic” come from?

Arithmetic comes from Middle English arsmetike, from Old French arismetique, from Latin arithmetica, from Ancient Greek ἀριθμητική, derived from ἀριθμητικός, from ἀριθμός meaning number, ultimately from Proto-Indo-European h₂er- or h₂rey-.

arithmetic (English): The mathematics of numbers under the operations...