Teachers are able to purchase a manual that includes the solutions and other material that encourages inclusion in the more general curriculum. Teachers are saved both the task of sourcing weekly homework and the time used in copying materials for their classes. The tear-out format means that the products can be sold cheaply, but the content means that they can still be considered as a text book because they comprehensively cover many elements of language skills appropriate to the students’ educational levels, and with which students should be familiar.