This study is conducted to further understand the direct and indirect contributions of executive functioning (visuospatial updating, verbal updating, inhibition, shifting) and arithmetic fluency to mathematical problem-solving in 458 fourth-grade students. Arithmetic fluency along with visuospatial and verbal updating were significant predictors of mathematical problem-solving at the end of grade 4. When the growth in mathematical problem-solving during grade 4 was analyzed, only arithmetic fluency directly and strongly contributed to students’ problem-solving at the end of grade 4. Inhibition and shifting (in combination with inhibition) were indirectly connected to mathematical problem-solving at the end of grade 4 via their arithmetic fluency. Arithmetic fluency plays a critical role and continues to do this in mathematical problem-solving. Furthermore, a decline in importance for visuospatial and verbal updating and increasing importance of inhibition and shifting (combined with inhibition) were found with regard to students’ ability to solve mathematical problems during grade 4.