I don't think binary is really subtle enough to have a fine gradation of shades of grey. I interpret "Understand binary" to mean something along the lines of "

I don't think binary is really subtle enough to have a fine gradation of shades of grey. I interpret "Understand binary" to mean something along the lines of "be comfortable with the notion that the numbering system we use has an arbitrary base (10), and that you can still have the same radix notation with a base of 2." If you get the joke about 10 people, you probably understand binary, and vice-versa. And now, for a completely different binary joke: I've got 1100011 but a bit ain't one.