I don't remember bringing a calculator for any of the tests. All I needed was some scrap paper and pencil (of course, with eraser). But I guess a calculator might come in handy for some. Probably, just about any "scientific calculator", that you can pick up in the school supply section of the store, would be useful. Stay away from the 4-bangers, because a better calculator my be useful later in life. The actual math involved for the test doesn't require much. The hard part may be remembering the actual formula or the formula derivation. IIRC, most of the wrong answers were ridiculously wrong. So it was easy to find the right answer. But note, that is just my opinion.
I was originally licensed as Novice in 1965, but didn't bother to upgrade until January 1999. Then, I took the Tech and General at a single VE session and two months later took the Advanced and Extra, again at a single VE session. That included the 13 and 20 WPM Morse tests, but you don't have to worry about that any more.
I don't know if they care any more, but at one time they didn't like you using programmable calculators, because you could easily program everything you needed for the tests. But, I don't know if they care any more. Since college (1967) I have only used RPN calculators or my slide rule. Well, except for my TI Programmer (calculates in decimal, octal, hex and binary), which I still need for some old computer work. But today, even on my PCs, I only use a RPN calculator. I have a HP41CV and a HP48GX, both of which are programmable. Plus I have 3 or 4 slide rulers. And, I always keep them handy.
My XYL (RIP, Nov. 2021) use to use a Casio calculator. She liked it because it had percentages and tax calculations. But then, she also used pencils that had the times tables written on them.
