Liven up learning as you help students understand abstract base ten concepts, including place value, estimation operations, fractions, and more. All units are made of bright, durable plastic. Starter Set includes 100 units, 30 rods, 10 flats, 1 cube, and Base Ten Book, designed for 3-4 students. Classroom Set includes 600 units, 200 rods, 20 flats, 3 cubes, and Base Ten Book, designed for 20-25 students.