Actually, as what i learned as a grade four now. Its actually that division is related to subtraction since division is subtracting repeatedly. Also division can be used instead of subtraction so you could be more faster
what is 120 divided by 30?
Well, everybody "knows" that it is more easier to do it to vertical way but, if you know how to use your hands to divide then they know how to divide. I could say "if you know multiplication, you know division"
Heheh ;D. Well i hope this helps