Background: Students commonly struggle with mathematics and mathematical problem-solving. Therefore, it is necessary to design and implement interventions aimed at improving these essential components of learning. Furthermore, the outcomes of these interventions can vary significantly and appear to be a function of a student's initial competencies in mathematics. Aim: This study attempts to analyse the influence of initial levels of mathematics competency with respect to the benefits of a specific intervention known as the Integrated Dynamic Representation (IDR). Sample: Participants were 288 students (aged 6-8 years) who were divided according to their levels of mathematics competency (low-medium-high). Methods: Students were assigned to the two primary intervention groups, experimental group (EG; students who received the IDR intervention) and control group (CG; students who followed the traditional instructional methods). All participants completed the Test of Early Mathematics Abilities (TEMA-3) both before and after the intervention. Results and conclusions: Although all the three competency levels of the EG improved, the progression was different for each level. Results showed that students with low competency level improved substantially more than the students with medium and/or high baseline competency level.