This file contains two different resources. The first is the guided notes that show the students the benefit of an explicit formula instead of a recursive one. Examples are given of how to write and simplify the explicit formula and then to use it to find a missing term.
The second resource is a practice sheet that I normally give for homework after going over the lesson with my students.
This can be used as an introductory activity or it can be used as a great review/refresher.
Please let me know if you have any questions.