Rachel asked:

What if we only had three fingers, how would this have changed our five fingered world?

Take a look at a book on numbers, and the notion of "bases" for numbering systems. We use a base
10 numbering system, because... yes, we have 10 fingers total. If we had three fingers (two plus
thumb, right?), we'd probably use base 6, actually a better system (base 12 is really the best,
because 12 has so many divisors). So the numbers would go: 0,1,2,3,4,5, 10.Why? Because "10"
means: "take the next power of the base". That is, in base 10, 1 is 10 to the 0. 10 is 10 to the 1. 100 is
10 squared. And so forth. So in base 6, what is 10? Yes, we write it (in base 10) as "6". 100 is six
squared, i.e., 36, as we write it. And so on. The base used in computers is base 2. So the numbers
for computers are: 0,1,10,11,100... and so forth. Think about it.

Aside from that... we would have less sure grips on tools, I guess... but I don't see any reason for big
changes. Playing piano would be much harder... we would have to redesign them.

Steven Ravett Brown