However, the expression: "mit den Hausaufgaben helfen" - is colloquial . The usua, standard l form is bei : Ich helfe dir bei den Hausaufgaben. Ich helfe euch bei der Arbeit. See also: http://www.duden.de/rechtschreibung/helfen Jemandem BEI der Arbeit helfen.

I would say that "mit" could be the best translation for English "with": z.B., "mit" can be used in sentences like "Ich lerne mit meiner Schwester". "bei" you can associate with ''at''. "Bei Smith" means "at Smith's", z.B. "Wir essen heute bei Smith" - "We're eating today at Smith's".

Hey Zachary, I just recognized that German is quite difficult when it comes to "with" because we have more than two words for it. So I'll try to explain it to you. Both "mit" and "bei" are prepositions but they are used differently. In your first example "Ich helfe dir bei den Hausaufgaben" you can choose both, i. e. "Ich helfe dir mit den Hausaufgaben" does say the same as your original example. Here you can choose "mit" or "bei" because you are trying to express an active participation in a process or action. Your second example expresses something spatially. It says, that some speakers A, B and C are in the near of / same room as/ etc. listener D or D and E. Unfortunately "bei" and "mit" does have a lot of meanings in german, so you need a dozen of examples to get a feeling for it.