Great #kidsactivities idea - the kids could help Get concrete pavers at big box home store. Use Outdoor paints in red, purple orange, blue, green, yellow (whatever colors you like). The black was used to paint on the numbers and the black was to outline the numbers so they would "pop." You'll probably need more of the white than any other color. Would make a great "hop scotch" play area.
32 Fun DIY Backyard Games To Play (for kids & adults!)