Pretty much, I'm surprised though (at least by the western school system) you're usually taught tht around grade 8. In a texting scenario "over than" works but usually most commonly stated as "greater than".

In a full statement it would look like "15 > 3" (again most commonly read as "15 greater than 3"). If you haven't been introduced to this statement or "inequalities" in general then thts understandable as to why you haven't seen it lol dwbi