“…Here, effects of the central executive seem particularly strong (Bull, Espy, & Wiebe, 2008;Geary, Brown, & Samaranayake, 1991;Geary & Hoard, 2001;Gersten, Jordan, & Flojo, 2005;Leather & Henry, 1994;Lee, Ng, Ng, & Lim, 2004;Lemaire, Abdi, & Fayol, 1996;Logie, Gilhooly, & Wynn, 1994;Passolunghi, & Siegel, 2004;Passolunghi, Vercelloni, & Schadee, 2007;Rammelaere, Stuyven, & Vandierendonck, 2001;Swanson, 2006;Swanson & Beebe-Frankenberger, 2004;Thomas, Zoelch, Seitz-Stein, & Schumann-Hengsteler, 2006). In a recent study by Geary, Hoard, Byrd-Graven, Nugent, and Numtee (2007) it was shown that all components of working memory, including the visual-spatial sketch pad, are related to math performance in school. The impact of the visual-spatial sketch pad on math achievement was also confirmed in recent cross-sectional and longitudinal studies (Berg, 2008;Bull, Espy, & Wiebe, 2008;Simmons, Singleton, & Horne, 2008; but see Leather & Henry, 1994;Lee, Ng, Ng, & Lim, 2004;Seitz & Schumann-Hengsteler, 2002;Swanson, 2006, for inconsistent results).…”