Previous research has shown the importance of conducting early interventions in mathematics in disadvantaged children. Solving arithmetical word problems is a field in which children particularly fail. In this study, preschoolers from disadvantaged French public schools (n = 101; Mage = 5–6) were taught strategies for using fingers to solve arithmetic word problems and compared with a control group. The intervention consisted of collective rituals based on learning finger patterns and 7 sessions spread over 4 weeks, for about 20 min, focusing on explaining how to use the fingers to solve problems. The results showed that the intervention has a significant post-test impact on the targeted transformation problem-solving skill and that children with lower performances in problem-solving at the pre-test benefited more from the intervention. The intervention also indirectly benefited the other problem-solving skills. However, there was no intervention effect on the arithmetic addition task. Our research highlights that an intervention focused on the explicit teaching of finger strategies for problem-solving can be successfully implemented into ecological learning contexts, especially in disadvantaged areas.