This Excel Spreadsheet provides a variety of number tower puzzles for students to solve. There is good variety in the problems and difficulty increases providing some nice challenges. Students are provided feedback for incorrect (Try again) and correct answers; however, entries must be entered in an exact format. If a student answers “y + 5” instead of “5 + y” the response “try again” will be received. Aside from the pickiness of the entry, this is a very fun and usable resource.