If you want the exact same app you can try going to the Play Store>Profile (touch your profile pic in the search bar)>Manage apps & device>Manage>open the drop down menu (touch "Installed" and select "Not installed")>scroll this list for your missing calculator app.
You may also check your manufacturer's app store, i.e. Galaxy Store for Samsung.
Welcome to Android Central! Are you certain you uninstalled it from the phone, or did you just remove the shortcut from the homescreen? Bring up your App Drawer -- do you still see the Calculator app there?