Discovering mathematics in one's own environment inspires students. Numerous everyday objects offer potentials for posing interesting and motivating measuring tasks. To organize the mathematics lesson outdoors, teachers can create so-called math trails in their environment using the MathCityMap system: a web portal and a smartphone app are available to prepare and conduct a math trail. Equipped with the app and measuring tools, the students work in small groups on the object side. Hereby, the MathCityMap app supports the independent and collaborative learning of students offering hints and direct answer validation. In the workshops, the participants get to know the system from a student’s and a teacher’s perspective. After a short introduction on outdoor learning and math trails, the participants experience a math trail supported by the MathCityMap app in the city center of Bologna. The second part focuses on the teacher’s perspective and starts with an introduction of the web portal and the presentation of criteria for meaningful outdoor math tasks. With this basis, the participants can create their own tasks in the MathCityMap web portal. As preparation for the workshop, the participants should download the MathCityMap app and register in the MathCityMap web portal. They should participate with their computer and have a smartphone/tablet on site. Let’s join the community!