I agree that HTM theory is not currently advanced enough to be used in writing a system to do math in the same way it is done in a human brain. That said, I think it could be fun (even if not very useful) to try and implement a much simpler calculator using HTM neurons arranged to simulate logic gates. A while back in another thread we talked about how the XOR operation could be learned in HTM. One could theoretically train up a whole lot of simulated logic gates to implement a calculator. For example, addition can be implemented with an ensemble of circuits like this:
