Children ages 8 to 12, or fourth through sixth grades, read sentences of typically 10 words, with a maximum of 20 words. The majority of works created at this level are between 20,000 and 40,000 words long. Children in high school aged 13 to 17, or in the seventh through twelfth grades, read for pleasure and information at the college level, which requires reading more complex material than younger readers. For most children, the optimal reading level is about grade four. That means that they should be able to understand the main ideas of the text and follow the narrative without too much help from a teacher. Some children, however, remain at a first-grade level for several years after starting school. These young readers need assistance from teachers or parents with more advanced books. Above a fourth-grade level, there's no harm in reading older material if you enjoy it and your parents let you. But most adolescents don't read at such a high level because it's not necessary for their education. They can get by on less literature than adults because there are other ways to learn about people, events, and issues outside their own time period. Adults, by contrast, cannot function well without reading at a higher level. That's why we recommend that everyone over the age of eight should be reading at or above a third-grade level.