This is an interactive worksheet that can be completed by students using tablets or I-Pads. It is interactive in the sense that when students enter an answer it gives immediate feedback whether the answer is correct or incorrect. Originally designed for students to complete and submit electronically. It was a follow-up to an introduction to simple interest. It does not require students to know interest formulas but understand the concept of increasing by a percentage. This worksheet was originally written using Google Docs and has been converted to an Excel worksheet here.