From the article itself it is clear that it was not a pure base 60 system. It was basically a base 10 system where the symbol changed at 10 and not 60. A pure b

From the article itself it is clear that it was not a pure base 60 system. It was basically a base 10 system where the symbol changed at 10 and not 60. A pure base would be like Hexadecimal where we use 16 symbols and 16 is equivalent to 10. I guess most of the human civilisation ended up using base 10 numbers because we have 10 finger. If we had 8 fingers, we would probably be using base 8. 64 would be our 100.