Introduction
Digital technologies have become a central part of teaching practice. Educators are expected to design attractive, up-to-date, and accessible learning materials using a wide range of digital tools. These include presentation software, graphic design platforms, video-editing applications, interactive quiz tools, authoring software, and learning management systems. While these resources offer many possibilities, teachers often face practical and pedagogical challenges when creating their own materials. This study explores the current use of digital tools for developing mathematics teaching resources in secondary education in Spain and examines the main difficulties teachers encounter in this process.

Methods
The study combined a review of commonly used digital tools with qualitative data collected from teachers. First, widely adopted software for creating presentations, visual content, videos, and interactive activities was analyzed in terms of usability, pedagogical value, and accessibility. Then, interviews and questionnaires were conducted with mathematics teachers working in a public secondary school located in the city of Elche (Spain), specifically in compulsory secondary education (ESO), with a focus on the final two years (ages 14–16), in order to identify common barriers in material design. Based on defined educational and technical criteria, one digital tool was selected and applied to develop a complete instructional unit for a mathematics course at this level.

Results
The findings show that digital tools increase flexibility, creativity, and student engagement in the analyzed educational context. However, teachers frequently report limited time, uneven digital skills, and uncertainty about how to align materials with learning objectives. The practical implementation demonstrated that careful selection of a tool and clear instructional planning significantly improve both efficiency and coherence in material design.

Conclusions
Choosing appropriate digital tools and applying clear design criteria can help teachers create effective and accessible learning materials in secondary mathematics education. Practical guidance and targeted support are key to improving the quality of digital instructional resources.