Teen boards: US version

Teen Boards, the first pair of Seguin boards, carry a child across the gap between nine and twenty. Sliding a numeral card over the zero of a printed ten turns 10 into 14 in front of the child's eyes, and the word fourteen stops being an arbitrary sound: it is ten and four. Used with bead bars, the boards join the spoken name, the written symbol and the quantity in a single exercise. US version, for children from three years who count confidently to ten.