Structure of Observed Learning Outcomes (SOLO) is a taxonomy that categorizes learning outcomes based on the complexity of cognitive integration, ranging from superficial levels of knowledge to deeper levels [1]. It promotes deep learning and critical thinking with reflective practice, serving as an excellent tool within educational systems [2]. So, SOLO can be applied in diverse educational and assessment contexts. SOLO taxonomy consists of 5 different levels of complexity, pre-structural, unistructural, multistructural, relational, and abstract, reflecting the development of human thought in the process of acquiring and organizing knowledge. They are therefore closely related to the process of thought construction, which takes place through the connections between synapses and their interconnections in the brain. At the pre-structural level, there is no knowledge about the issue in question. There is a single point of knowledge at the unistructural level. By the time one reaches the multistructural level, several points of knowledge are integrated, but their interrelationships may not necessarily be comprehended. The relational level comes into action when it becomes possible to establish relationships between different types of knowledge and understand how they connect in a more complex way. At the abstract level, the application of knowledge to new situations and contexts; Students at this level demonstrate a deep and flexible understanding of the material.

Based on previous studies [3,4], this study pursued the research on how to build test questions that range from basic concepts to more complex concepts, according to levels of complexity [5], enabling the teacher to detect students' skills about a given topic and at what level of complexity they are in, in order to make judgments on which skills and competences are lacking for further higher-level learning. 70 students from a mathematics course in higher education were evaluated on specific topics in the syllabus. For this evaluation, 2 different teaching methodologies (MA, MB) were applied to the same exercises, with the aim of comparing how each approach impacted student performance. In the 1st question, 35 students answered a question using MA, which consists of questions prepared progressively, organized by levels of increasing complexity. The other 35 students answered the same question but using MB, which is composed of questions prepared in a traditional way, without explicit division by levels of difficulty. In 2nd question, the methodology applied will be reversed for the groups: the 35 students who had answered the first exercise using MA will now answer the question using MB, and vice versa. This was done to ensure that all students were exposed to both methodologies and that the impact of each could be compared fairly. In the 3rd question, all students solved the question by levels of complexity, with the aim of students reaching the highest level of understanding, the abstract level. This question was designed to challenge students to apply knowledge in a more integrated and in-depth way.

The approach followed in this study made it possible to analyse how different teaching methodologies influence the development of students' cognitive skills, related to the complexity of problems proposed, in addition to observing if progression in difficulty levels contributes to deeper and more abstract learning.

Keywords: SOLO taxonomy, levels of complexity, mathematics, higher education, test questions.