Abstract:

The Erasmus+ project Teacher Training Tool in Mathematics (TeToM) was launched in 2025 by an European consortium of six partners across four countries: University of Bielefeld (Germany, coordinator), University of Bayreuth (Germany), University College of Teacher Education Styria (Austria), Kore University of Enna (Italy), University of Córdoba (Spain) and the Spanish Federation of Mathematics Teachers’ Associations (Spain). TeToM develops a modular professional development programme that helps teachers address students’ difficulties with mathematical key skills at two critical transition points: the start of Grade 5 and the start of Grade 7. Across European education systems, a substantial proportion of students enter lower secondary school without secure understanding of foundational arithmetic and early algebraic concepts. These gaps tend to persist and can hinder access to subsequent curriculum content, making early and targeted support essential. A key challenge is the “diagnosis–instruction gap”: teachers often find it difficult to translate diagnostic results into effective and content-specific support measures, especially under time and resource constraints. While screening and diagnostic tools can identify learning risks efficiently, easily accessible and classroom-tested materials that connect diagnostic profiles to concrete instructional decisions in arithmetic and algebra are still scarce.

TeToM addresses this gap by integrating two evidence-informed strands:
(a) group-based screening of mathematical key skills (skills whose absence substantially constrains further learning), and
(b) established diagnostic–didactic approaches that link assessment results to instructional support.

TeToM designs modules that guide teachers through:
(1) interpreting screening and diagnostic results,
(2) selecting focus skills and learning goals,
(3) planning adaptive support in regular lessons and additional support settings and
(4) implementing practice-tested tasks and materials.

To support sustainable uptake beyond individual classrooms, TeToM combines teacher professional development with a training of trainers pathway and provides multilingual, digitally accessible resources for flexible hybrid use. The paper presents the conceptual framework, the modular structure and the scope of the Erasmus+ funded project.

Keywords:

Professional teacher development, teacher training, diagnostic-informed instruction, mathematical key skills.