In Sequential Spelling Volumes 1 - 7 You go from all to tall to stall to install to installment with these easy-to-use books that will help your students achieve spelling mastery by spelling in sequence, in a logical, pattern-driven context. Every Sequential Spelling book contains 180 lessons (about 72 pgs.). If you follow the public school year, then it is enough for one full year. If you choose to give one lesson every day, you will be able to complete one level in six months. If you have more than one child, you may also want to buy extra Student Response Books (W310) to accompany your Sequential Spelling book in order to conveniently record your children's responses without them being able to see their responses from the previous day. While this is not absolutely necessary, it is so convenient, we highly recommend that you also purchase one for each child.  The first one, of course, is FREE