This is all an update tactic. With this, Samsung is removing weight from the firmware update packages. “Weight reduction, bro”. This allows Samsung developers to focus on more crucial parts of its software without worrying about wedging in the basic app updates. It will also speed up the firmware update release dates, rather than delaying them.
Right now, Samsung Calculator can only be downloaded on Android 7.0 Nougat or higher. If you have a phone with Android Nougat, hit the Play Store and download it.