This material is used to introduce the concept of negative numbers. The material consists of a presentation tray containing 6 boxes of Bead Material, 1 box containing 5 sets of Colored Bead Stairs, 1 box containing 5 sets of Negative Bead Stairs, 1 box containing 1 Black And White Bead Stair, 1 box containing 23 Golden Bars Of 10, 1 box containing 1 Red And White Bead Stair and 1 box containing 23 Gray Bars Of 10.