The aim of this paper is to present an application that I created for use on Android smartphones, which helps 9th grade teachers with the content: Pythagorean Theorem, calculating areas of flat figures and Bháskara's Formula. The app can help students solve the exercises, which are shown step by step. Because there are still teachers who are not tech-savvy, the app was developed in a clear and intuitive way, making it easy for both the teacher and the student to use. It is a way of encouraging elementary school teachers to work with cell phone technology. Some activities have been suggested for use in the teaching and learning of the 9th year of elementary school with the content mentioned. It is hoped that this app will encourage students and teachers to use digital technologies to promote the teaching and learning of mathematics.