Early mathematics skills are an important predictor of later academic, economic and personal success. Children born preterm, about 10% of the US population, have an increased risk of deficits in mathematics. These deficits may be related to lower levels of executive functions and processing speed. We investigated the development of mathematics skills, working memory, inhibitory control and processing speed of healthy children born very preterm (between 25 and 32 weeks gestational age, n=51) and full-term (n=29). Children were tested annually from ages 5 to 7 years. We found persistent lower overall mathematics skills in the preterm group, driven by differences in more informal skills (e.g. counting) at earlier time points, and by differences in more formal skills (e.g. calculation) at later time points. We did not find significant differences between preterm and full-term born children in spatial working memory capacity or processing speed. However, these cognitive measures were significant predictors of mathematics skills in the preterm but not the full-term group, hinting towards the use of different strategies when solving problems.