Two feature requests: Avoid asking the user + or . It's the easy and obviuos part. Just click 3, 7, 21 and the computer shold show for half a second and paint

Two feature requests: Avoid asking the user + or . It's the easy and obviuos part. Just click 3, 7, 21 and the computer shold show for half a second and paint 21 as done. Paint in a different color the numbers that are used in both grids. Now it's too hard to remember if I used all the 5.