This book series is great for children ages 7 - 13, as they can relate with what Frank and Joe are doing and what mystery they are attempting to solve. The book, The HBs - Trouble at the Arcade - Book 1, discusses problem solving skills, working together as a team, listening to others ideas, and being a good friend/sibling. The comprehension questions in this product relate with the text as well as students own experiences. Vocabulary words, their meanings, and example sentences are presented in