# Augmented Reality as a Didactic Resource for Teaching Mathematics
## 1 Introduction  
In our society, new technologies are increasingly important in our daily lives: they facilitate tasks and allow us instant access to information in many ways. In addition, in recent years the number of jobs that depend on them has been gradually increasing, so it is necessary that children and adolescents get in touch and become familiar with them from an early age. This importance is reflected in the Spanish Education Law. It considers new technologies as a fundamental piece of the methodological change that achieved the objective of improving educational quality. Likewise, information and communication technologies will also be key tools in teacher training and in the learning of citizens throughout life. Our intention in this study is the creation of a didactic proposal for the teaching of mathematics, especially in the geometry content block, for secondary mathematics teachers, and also for future teachers in their master training courses. Although it is true that educational innovation does not necessarily have to be linked to the use of new technologies, the problem of visualization in geometry cannot be solved simply with manipulative teaching material, which has traditionally been used in the classroom, such as polyhedra made of paper and wood or with vertex and edge assemblies. The use of augmented reality (AR) would allow us to develop mandatory aspects of the curriculum, such as the use of new technologies, and improve visualization in geometry so that this block does not remain as a mere calculation of areas and volumes by applying formulas. One of the problems of new technologies is not only their economic cost, but also the fact that the teacher must be familiar with them, so that it is less expensive to implement them in the classroom. The idea of this project is to facilitate this point, explaining in detail how to make an app with accessible hardware and free software so that any teacher can use it in their math classes. In previous work [1; 2] we discussed the importance of the use of accessible hardware and free software so that the educational use of augmented reality (AR from now on) is feasible and can be used in classrooms without problems. In addition, augmented reality educational experiences have been successfully designed to teach different educational contents of science and mathematics, although the interface has not always been the screen of a mobile device. The motivation of the students and their involvement with learning are key to achieve effective learning. In this case, AR-related technology plays a fundamental role as several investigations have shown [3; 4; 5; 6; 7], in which the increase in student motivation with the use of AR technologies has been measured. The advantage of AR is its similarity to games to which students are accustomed in their leisure time. Hence, its implementation in the classroom is very natural for them. AR has become an innovative, useful, and effective teaching tool in different educational fields [8; 9; 10]. Furthermore, some authors consider that AR systems help students to develop skills which can be developed in other environments, but they are developed more effectively through the use of AR [11]. New technologies are a fundamental tool to facilitate the learning of curricular contents of different subjects. In this paper we focus on mathematics, and specifically on the geometry content block. In usual geometry classes everything is focused on figure recognition and the application of formulae to calculate areas and volumes. However, when the content is more complex and involves visualization, the acquisition of spatial skills, and the application of advanced strategies, traditional resources do not work. AR helps in these aspects, as seen in similar works in other educational levels [12; 13; 14]. Moreover, understanding geometric concepts and relationships, students have an increase in creativity with AR technology [15].