This was a gift to my kids from their Great- Grandmother. It is great for indoor use during this cld wi er... AND Covid-19. 
We set it up in the hall way. My kids, ages 4 and 5, play "best out of 5" and are using the numbers to make adding and math fun. 
Note: when using it outdoors or at further distances, the washer work WAY better- but I wouldn't use them indoors