The objective of the investigation is for university students to achieve the construction of the definite integral concept using open source software. The teaching activity encompasses everyday life problems where the constant, linear and the non-constant change rate functions are present. The accumulated change is approached using the geometric approximation of the area under the curve. A qualitative analysis was made to identify the level of understanding acquired, its development and the mathematical learning objects implemented during the lesson plan activities, using worksheets where the participants record their observations and answers. The level of comprehension was different for each student; participants who were able to visualize the relationship between the area under the curve and accumulated change were identified, applying the concept to solve a problem, although the majority of students had difficulty applying the concept.