You put the subject as math, so I’m not sure if this will be the correct answer, unless you meant English.
The word “up” in English can be used as a verb or a preposition. If it’s used in a verb form then it’s being used in an informal way. For example if you’re talking to a friend or relative. If it’s being used in a preposition then it’s being used in a formal way. For example if you were talking to your boss at work or a teacher. So depending on what you’re learning or the sentence that is using the word “up” would on your answer. I hope this helps.