“…Here, we based our current experiment on previous work in complex arithmetic that showed that both adults and children had poorer performance on harder than on easier problems, whether difficulty of problems was defined on the basis of the size of operands, on involving carryover, or both (e.g., De Smedt, Holloway, & Ansari, 2011;Geary, Cormier, Goggin, Estrada, & Lunn, 1993;Geary, Widaman, Little, & Cormier, 1987;Green, Lemaire, & Dufau, 2007;Hodzik & Lemaire, 2011;Lemaire & Arnaud, 2008;Lemaire & Calliès, 2009;Widaman, Geary, Cormier, & Little, 1989). The present work aimed at replicating such problem difficulty effects on children's performance in complex arithmetic and at testing interactions of problem difficulty with other variables (i.e., children's age and strategies).…”