5 and 10 are arbitrary numbers though. Halving and doubling are really the only special operations, and base-8 or base-16 would be superior to 10 or 12 for those.
The topic of this thread is why the base 10 number system is less than optimal, and a different base would be better. Obviously having to convert to other bases when we use a base 10 system normally is inconvenient, but that's not the point.
