Re: it just doesn’t add up.
"It seems that El Reg has some Chinese agents active tonight. Why else would the posts suggesting 'sending data to china' have downvotes?"
I didn't give any of the downvotes, but I have an idea. Maybe because it's ridiculous. For one thing, it's a calculator. How many people who aren't planning to hack their calculator get one, turn it on, verify that it can do calculations, then go into a completely different part of the interface and give it WiFi credentials? Unless you give it a connection, it won't be able to send any data to anybody. Also, it is going to get some numerical input, and that's it, so where is the useful data coming from? I recently typed the following digits into a calculator: 3604.59/(40*8). Anyone who can correctly explain why I wanted the result to that calculation from no other context gets a free upvote. Since it's based on an earlier calculation, it's a bit unfair. Here's another one you can try: 3*261*7.
I'm sure there's a lot of pointless code in there, and it's theoretically possible that it's designed in a malicious way, though it's not likely, given that spamming these out to anyone who wants a relatively poor calculator isn't a great targeting system. Even if it was, it's not going to focus on spying on user's calculations. It has WiFi not because there's a secret plan, but because the parts they had sitting around supported WiFi, so if they're going to try to make a calculator out of them, it's also going to have the hardware.