How big are the cells?

Sized so every number is at least 7 pt and a pencil fits: about 14 mm for toddlers, 10 mm for kids and seniors, 6.7 mm for bold and easy, 5 mm for detailed (Simpler detail makes them bigger, More detail smaller). With color by code, the cells grow to fit the widest label. Cells cut small by the edge of the page join their neighbour, so every cell holds its number. The cells' lines are lighter than a coloring page's (0.8 to 1.75 pt by readers), because the picture is in the colors.