Sorting rings can be used to teach several basic concepts and maths skills. Use the rings singly to add and subtract objects in and out of the ring to aid understanding. Alternatively, use two or three rings together and create Venn diagrams to develop sorting, analysis and counting skills. rings are flexible and can fold into an oval for easier storage. Circle size 500mm diameter. Each folds into an oval approx. 360 160mm for ease of storage. Pack of 6.