Grades K - 3. The Unifix® 1-10 stair consists of ten joined vertical grooves in which joined rods of Unifix® Cubes are placed to match the values printed at the top of each groove. Cubes placed in the grooves demonstrate each number as a grouping of ones. Ideal for reinforcing and teaching number, ordering and sequencing. The stair is made of durable plastic and measures 8.5" x 8.875". Cubes are not included.