Pretty cool mechanic for a puzzle game, although I was having troubles understanding what's the goal/win-state, it's not written anywhere, neither in the game nor on the game page. It's says "paint with the appropriate number" on this jam page, but no mentioning of the mechanic of addition, which was not obvious for me. It also starts right away with pretty difficult level, first levels in such games are usually simple tutorials that teach main mechanics, I think here such tutorial levels would be relevant.