to answer your question, the seedling leaves (cotyledons) are not counted the first set of true leaves is the first true node, and every set after that is a node, the space between the nodes is called an internode
They are going to bash you for asking that question, I asked it on page 222 i think and they got all pissy. they are up on there high horses and are to good to answer anyones questions...
Peace,
natty