Daniel Kahneman and Amos Tversky have changed the way we think about human rationality. Based on their contributions, the Enlightenment notion of rational humans thinking according to the laws of logic and probability had to be replaced by a more realistic conceptualisation of human thinking. However, their experiments on the so-called “errors” of the human mind were countered by a plethora of other experiments aimed at identifying the conditions that reduce or even eliminate these errors. Both the discoveries of Kahneman and Tversky, and the reactions they provoked, also had an impact on the way we teach critical thinking and probability in school. Maths educators have been prompted by these discoveries to find new, more adaptable ways to address reasoning and decision making under uncertainty in the classroom. This paper presents tools and methods that have been developed to promote logical reasoning in tasks on the so-called conjunction rule and tasks on strictly probabilistic reasoning. These tools use adequate and dynamic representations partly inspired by Barbara Tversky’s work on dynamic visualizations and the way the human mind constructs thoughts. The two studies reported here were carried out in schools and demonstrate the effectiveness of these tools. .