"It is my pleasure to inform you that your grade in NumMeth..., strike that; um, er, whatever this course is really called, is an A.
I think your first homework (the gold star one) said it all: you know very well how to combine rigorous technical content with your ability to communicate that content. You seem to have that knack of an easy, somewhat conversational style while still expressing difficult material in a professional manner. I believe these skills will take you far; you are definitely one who "get's the job done, done well, and done with good spirit". (At least in numerical analysis, anyway!)
Best wishes at MIT and beyond!
- Tom"