Twelve picture cards fill a grid, each showing a bright illustration with its word printed underneath and a box waiting for the article. A child writes a or an into the box rather than picking from two choices, which is a step up from circling.
Every picture is labeled, so nothing rests on guessing what the drawing is meant to be. That matters more than it sounds for this skill, since a child who calls the bird a robin would need a different article, and naming it for them keeps the exercise about the sound. The twelve run six and six, with octopus, envelope, alligator, eagle, onion and eraser carrying the an side.