To Split, To Break
Transitive verb and Godan verb
わる
7割る2が3で余りが1になることを解くのに一時間かかった。
It took me an hour to figure out that 7 divided by 2 equals 3 with a remainder of 1.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means divide so the verb vocab version is to divide.
The reading you learned with the kanji is the one you'll use here. It's the わ one, though, making it わる.