“…As examples, 6-year-olds can choose the game with the greater probability of winning when this is determined by a ratio of two continuous quantities (i.e., a doughnut divided into a red part and a blue part) (Jeong et al, 2007), and 4-year-olds are able to perform simple operations on fractional amounts or to match figures according to visuospatial ratios (Mix et al, 1999;Sophian, 2000). Barth, Baron, Spelke, and Carey (2009) showed that 6-and 7-year-olds are able to apply multiplicative transformations to discrete quantities and, in particular, to represent the half of a set and compare it with a third set. Their performance varies with the ratio between the to-be-compared quantities, suggesting that children operate on mental magnitudes.…”