“…In this case, overall maturation, which is certainly fast at that age, might have led to the improvement of all skills in all groups. However, we do not think maturation plays a sole role, as other studies with waiting control groups consistently showed differences when compared to the intervention groups (e.g., Gracia-Bafalluy and Noël, 2008;Jay and Betenson, 2017;Frey et al, unpublished). Moreover, other studies focusing on other numerical precursor skills, or including a broader range of such skills, have shown intervention effects in kindergarten children (e.g., Kaufmann et al, 2005;Krajewski et al, 2008;Praet and Desoete, 2014).…”