Our number system isn't optimal either. It would have been nice to have digits in the range -5..5 rather than 0..9. This would simplify a lot of things. Elementary multiplication tables reduced to a quarter of the current size, addition and subtraction become basically the same operation. Same for truncation and rounding. It makes calculations a lot easier.
There was an article about it in New Scientist of April 22, 1982. I loved it.
Jeroen Belleman