This was revealed during a Q&A session that Apple’s software chief Craig Federighi did with YouTuber Marques Brownlee, in which he explained the reason why Apple still has not brought a calculator app onto the iPad even until today. The short answer is that it is because they have yet to figure out how to make the “greatest iPad calculator app”.
According to Federighi, “There’s some things that we have not done because we would want to do something really distinctly great in that space. We want to do it when we can do it really, really well. And we honestly just haven’t gotten around to doing it great.” in case you didn’t know, Apple did actually plan to include one in the original iPad, but that idea was scrapped by Apple’s co-founder, Steve Jobs, because it was essentially a blown up version of the iPhone’s calculator app.
Federighi notes that the company could eventually one day include such an app, but we imagine that it might not necessarily be particularly high on Apple’s list of things to do when it comes to iPad development, so don’t hold your breath.