LOL! Same here!
I remember having to spoon feed them basic facts. In some cases it was like leaving a trail of bread crumbs so they could find their way to the logic.
One of the things they hated most about me was my strict adherence to encumbrance. I remember on one occasion as I checked the character sheets before play started, I looked at Chris and here's how that went:
Me: What the hell is this?
Chris: What?
Me: 100,000 gold pieces? Are you out of your mind?
Chris: I have an 18 strength!
Me: *sigh* Let's work with me here - a gold piece weighs about 3 ounces, right?
Chris: OK. Yeah. So.
Me: So roughly 5 gold pieces is a pound, right?
Chris: Yeah.
Me: So that means that 50 pieces is 10 pounds, 500 pieces is 100 pounds and so on. So by the time you get to 100,000 gold pieces, you're talking about 20,000 pounds. So, congratulations! You've crushed yourself to death under the weight of a fully loaded Peterbuilt. *Tears character sheet in half and hands it back to him*