The formulation of learning objectives is considered an important task for teaching at all educational levels. However, teachers tend to trivialize learning objectives and consider them as part of an administrative requirement. This study sought to characterize the specific learning objectives for two school mathematics tasks posed by primary teachers in training, and to study the differences in the objectives proposed for each task. By means of a semantic questionnaire, the proposals were collected, classified and analysed using categories based on a triad of components for a specific objective: capability, content, and context. The responses show both an instrumental approach--where knowledge consists in mastering techniques and algorithms useful to furthering certain behaviours and attaining specific objectives--and a structural approach--where knowledge consists in a structured system of formalized rules and concepts based on the deduction. Moreover, this expectation depends on the kind of school task.