The full Windows version can be ordered here: https://fingertainment.itch.io/harryrabby2-adding-4-numbers-full
Here is the link to the free version: https://fingertainment.itch.io/harryrabby-elementary-math-adding-4-numbers
If you want to play on android phone: https://play.google.com/store/apps/details?id=com.harryrabby.add4free
