Math Blues

On a short note, I'm having a fit of headache today. I had a long talk with one of the flunking students in my programming class after class, and I finally figured why he had such a hard time.

Here are some answers to questions I've asked him after trying to figure what is the problem based on a few simple programming assignment:

Part I
//Making a Money Exchange program
me: Okay, you withdrawn 1,512 THB (local currency) from the ATM. Now how many 500 THB bills will you get?
him: 20.
me: :o

Part II
me: What is 8 multiplied by 8?
him: 40?
me: ???
him: Not correct? 56?
me: :o
him: I'm sure now, its 48!
me: >:(

Part III
me: What is 11 divided by 2?
him: 6?
me: No?!
him: No its 5.5.
me: Assume you got 5, what is the remainder?
him: 2.

I'm starting to wonder if I'm teaching a undergrad class or either I'm a primary school teacher. Somehow I have a reason to believe there isn't much of a difference between the two levels ???