[Terra smiles down at him and then glances over his notes.]

Well do you remember your first year? A lot of the concepts can be simplified down to that. Just as newtons laws are the basics for physics. Matter is not created or destroyed only changed.

[A thing finger lightly taps the page that he's looking at.]

See this variable here? That's the size and while doing the spell, much like the equation it's exact small movements.