Just download PCalc Lite, then. But seriously, how often do you need to perform calculations on your computer that lacking a calculator app is a make-or-break proposition? Never mind the quantity of free web-based calculators or basic math operations supported in search engine search boxes. If having a calculator is so important to you that a device isn’t worth $600 without one, perhaps you’d be better off owning a dedicated calculator or just buying a computer with a calculator?
But it isn’t actually about the calculator app, is it? (Because, if you wanted an iPad, you could almost certainly float the money for PCalc - or use PCalc Lite. And your phone almost certainly has a calculator of its own, and the iPad’s missing calculator app would likely be no more powerful than your phone’s. And dedicated calculators are far cheaper than an iPhone or iPad, especially if you just want a model with scientific operations and a multi-line display.) It’s more that you view the lack of calculator as an easy potshot against iPadOS, I’d guess. It’s kind of a lazy potshot, though, as I’d imagine most iPad users have an even more convenient calculator in their pockets nearly constantly (and those that don’t could easily justify the price of a good 3rd party calculator app over that of a smartphone with a calculator app, an Android tablet with a calculator app, or even a dedicated physical calculator).
The whole calculator app business just strikes me as a very disingenuous argument against iPadOS, since it’s one that’s basically a non-issue, the iOS calculator itself isn’t that great, and third party calculators (or even actual calculators with the same level of functionality as iOS’s) are super cheap and widely available. If you desperately needed a calculator as an iPad owner, you wouldn’t be starving for choice. So it seems like a bad-faith attack on iPadOS using an easily debunked trivial issue. iPadOS certainly has and has had significant flaws (it lacked a proper download manager in Safari for years, for instance), but the lack of a bundled calculator app is hardly a serious one.