Empirical evidence suggests that working memory (WM) is closely related to arithmetic performance. WM, which is the ability to monitor and update recent information, underlies various cognitive processes and behaviors including planning, self-regulation, and self-control. However, only a few studies have examined whether WM uniquely explains variance in arithmetic performance when other WM-related domain-general factors are taken into account. In this study, we examined whether WM explains unique variance in arithmetic performance when planning, self-regulation, and self-control are considered as well. We used the Tower of London task as a measure of planning, self-rated reports as a measure of self-regulation and self-control, and WM measures, to test which of these domain-general functions predicts complex multiplication performance. Results showed that planning predicted multiplication accuracy and self-control predicted response time, while WM and self-regulation did not predict complex multiplication performance. Although WM was not a direct predictor of multiplication performance, it possibly exerted its influence as part of planning ability. We suggest that complex multiplication is not predicted by WM per se, but rather by WM-related general cognitive and behavioral factors, namely self-control and the planning component of executive functions.