On Debian templates I find “gnome-calculator”, “deepin-calculator”, “kcalc”. To find these I wrote apt search calculator. On fedora qubes instead you search with dnf search calculator.
But searching though the package managers (dnf/apt) yields some unrelated / bad results sometimes. So my suggestion is to just use a search engine in your case I would look for best calculator for debian for example. I wrote more in detail in my software installation guide: