Routh FREE is an Android app that allows users to perform stability analysis of input-output systems using Routh-Hurwitz criterion. With this app, users can generate the full Routh-Hurwitz table, find all poles from the characteristic equation, and visualize them in the complex plane. The app is perfect for professors who need to generate random exercises for their class or students who need more exercises to practice for their exams. The Routh app now has an exercise generator that randomizes exercises for 5 categories of exercises, including general problems, row of zeros, problems with an unknown gain K as a coefficient of the characteristic equation, zero in the first column, and stability of closed-loop systems. If you need more features, you can download the full version. Routh FREE is a free app available for download on the Google Play Store.