The actions carried out by children are a mechanism that enables them to come into contact with their environment, assimilating it, acting on it, and thereby transforming it. From this perspective, an exploratory study has been designed to analyse the actions carried out by 87 children aged 1-3 years old in two task-situations involving the manipulation of materials. These actions have been linked to the acquisition of early informal mathematics knowledge according to gender, the type of action and age. The results show that there are no differences in relation to gender and that the types of actions appear in a gradual way, depending on the type of contents and the children's age: actions related to sensory qualities and numbers and operations are the most common; actions related to positions and forms appear around age 2, and actions associated with measurable attributes appear from approximately 3 years.