To Split Something, To Break Something
transitive verb, godan verb
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 or to split something.
It can also mean to break something, as in ワイングラスを割る (to break a wine glass). After all, you’re technically dividing the object into parts if you break it, right?
The reading you learned with the kanji is the one you'll use here. It's the わ one, though, making it わる.
It took me an hour to figure out that 7 divided by 2 equals 3 with a remainder of 1.