Didax Unifix Ten-frame Train Manipulative Set includes 10 cars, a 10-frame spinner and a teacher's guide with games, teaching ideas and assessment instructions. Manipulative teaches kids different ways to develop a concrete understanding of the concept of ten by connecting train cars, each holding 10 unifix cubes. Ideal for individual or a small group use wherein children can see and feel 10 and some more, 20, 30, etc by filling up the spaces and connecting the cars. The new manipulative consists of 20 unifix cubes. Ideal for grades K - 2. Sold as 10 per set.