Why would doing a bunch of basic arithmetic produce an entity that can experience things the way we do? There's no connection between those two concepts, aside from the fact that the one thing we know that can experience these things is also able to perform computation. But there's no indication that's anything other than a coincidence, or that the causation doesn't run in reverse, or from some common factor. You might as well say that electric fences give rise to cows.
On the other hand, what else could it be? Consciousness is clearly in the brain. Normal biological processes don't seem to do it, it's something particular about the brain. So it's either something that only the brain does, which seems to be something at least vaguely like computation, or the brain is just a conduit and consciousness comes from something functionally like a "soul." Given the total lack of evidence for any such thing, and the total lack of any way to even rigorously define or conceptualize a "soul," this is also absurd.
Consciousness just doesn't fit with anything else we know about the world. It's a fundamental mystery as things currently stand, and there's no explanation that makes a bit of sense yet.
