Two tall boxes head the page, one labeled A and one labeled AN, and twelve labeled picture cards wait below a cut line to be snipped out and glued into the right one. Rabbit, pencil, ball, sock, banana and tiger belong on one side; astronaut, ox, arrow, eye, iguana and apron on the other.
Sorting into columns lets a child change their mind, which a written answer does not. A card can be laid in a box, looked at again and moved before any glue is opened, and children who are still working the rule out tend to do exactly that. The six and six split also means a lopsided finish is a signal to check, without a single mark on the page.