Mathematics is simply a language persay of quantities via relationships. Mathematics as we know it didn't exist I think until the Greeks. They used to use language - one and one is two. Then some guy came along and said, hey, let's have a symbol for one AND one, and then we get +. Etc... for all the other basic operators.
deep_tought, look at like this: You have a cup in your hands, and I give you another cup - you have a cup, and a cup. I give you another, and you have a cup, and a cup, and a cup. This can get complicated if you're running a cup store, and you need to keep track of your many cups. Eventually you learn that 1 cup + 1 cup + 1 cup = 3 cups. You're just assigning symbols to a quantity. It's a bit abstract, but stay with me. If you'd like to extend your store to say, cups and balloons, well you won't say "I have 3 cups, and a balloon and a balloon and a balloon." You'll eventually learn to say 1 balloon + 1 balloon + 1 balloon = 3 balloon. I hope you get what I'm saying. Eventually you decide you want to be a physicist and you need a way to measure objects to compare them. So you get a bar of iron, and you say that "this amount of mass is 1 kilogram" and you compare every thing you weigh to this bar of iron. You can say I weigh 3 iron bars. That just means you weigh that 1 iron bar + 1 iron bar + 1 iron bar = 3 iron bar. Or, 3 TIMES the iron bar.
Acceleration is a magnitude of some distance in some direction over time*time. And you are taking that iron bar (or whatever we used to define the kg) and relating the weight to the distance over time (squared) with a direction. This is how you define things; relationships. We call this relationship force.
Mathematics is just all about relationships. Physics is a bit more specific, as it applies math specifically to certain quantities, etc... You could break all of our definitions of time, weight, etc... down to some physical piece of matter or something with which we are comparing. Gotta start somewhere.
And I don't get what you are saying about dimensions, how does multiplication "change" dimensions?
Math doesn't actually DO anything, it is descriptive, i.e. it describes!