To infinity and beyond!
Writing for BBC Future—because, why not?—Richard Fisher discusses The numbers that are too big to imagine. He starts well enough, with a little childhood reminiscence:
What's the biggest number you can think of? When I was a child, it's the kind of question we'd ask each other in the school playground. Someone would say something hopelessly naïve like "a billion billion billion", only to be outstripped by a peer who knew about trillions, squillions or kajillions (it didn't matter if only one of those is real). Eventually, someone would remember that they knew the winning answer: "infinity!" But the smugness was short-lived. Another kid – with a mathematical mic drop – soon pointed out that they could beat it, with "infinity… plus one".
Richard Fisher, The numbers that are too big to imagine, BBC Future
Which isn't quite the mic drop that he suggests it is. He goes on to note that natural numbers are infinite. Infinity isn't a number so much as a concept, or a construct; you can't add to it. Infinity plus one is still infinity. By the same token, infinity minus one is…infinity.
Besides, the real mathematical mic drop, for any child growing up in the post-Toy Story era, is to channel their inner Buzz Lightyear: infinity and beyond. Plus one.
>∞ + 1
Fisher later discusses large numbers, or at least their US versions, without explaining how those differ from anything I should care about. So I stopped reading at that point. Note to Auntie Beeb: if you're going to specify that a characteristic is region-specific, at least give some explanation; in this case, I suspect it's a matter of three zeros. Or six. (shrug)
In US English, a billion is one thousand million (109, short scale), whereas in British English it was historically one million million (1012, long scale). That's changed in recent years, so that British billionaires can be a thing, allowing the likes of James Dyson; Jim Ratcliffe; and Hugh Grosvenor, Duke of Westminster, to join the rarified ranks of Elon Musk; Bill Gates; and Jeff Bezos. Otherwise, they'd be forced to slum it with the other millionaires. And we can't have that now, can we?