An in-depth activity that involves a real-world problem about credit card debt. Learners are given a scenario in which Isabella plans to stop using her credit card and pay off the balance by paying a fixed amount each month. The first task is to determine how long it will take for the balance to reach zero using a given interest rate. Your mathematicians create a recursive process to compute values and interpret values within the context to answer additional questions. The activity is presented on an interactive webpage which includes a simulated spreadsheet with data displayed and a drag-and-drop feature to enter responses.