The listing, Think It Through Tiles - Discovery Toys +5 lesson books has ended.
This is Think-It-Through Tiles from Discovery toys. Your child puts a tile down that represents the answer to a problem. When all the problems are completed from a page, you turn the tiles over and you open it up. You are given a pattern that the tiles should be in. If the pattern matches the one given, then your child knows all the answers are correct. If the pattern does not match, then one or more problems are wrong. I'm trying to describe this the best I can so you might want to look it up to get a better (ok, way better) idea on how cool and fun this is. I homeschool and this has been a great tool for us. And because of that, these are used. There is a little bit of writing (mostly my notes on the kids progress) and some marks here and there. Overall these are in decent shape. The tiles and tile case are in great shape.