For example, in English, the numbers beyond 20 are named by a decade (twenty) that is followed by a digit (one) and their names follow a logical pattern (twenty-one, twenty-two, twenty-three, etc.). In Chinese, the numbers from 11 to 19 are similarly constructed (ten-one, ten-two, ten-three…). But in English, the names of the numbers between 11 and 19 either reverse the order of the decade and the digit (sixteen, seventeen) or are entirely arbitrary (eleven, twelve). The difference in the regularity of these two systems makes a big difference to the children who must learn them. It is obvious to a Chinese child that 12—which is called “ten-two”—can be decomposed into 10 and 2, but it is not so obvious to an American child, who calls the number “twelve” (see Figure 11.5). In one study, children from many countries were asked to hand an experimenter a certain number of bricks. Some of the bricks were single, and some were glued together in strips of 10. When Asian children were asked to hand the experimenter 26 bricks, they tended to hand over two strips of 10 plus six singles. Non-Asian children tended to use the clumsier strategy of counting out 26 single bricks (Miura et al., 1994). Results such as these suggest that the regularity of the counting system that children inherit can promote or discourage their discovery of the fact that two-digit numbers can be decomposed (Gordon, 2004; Imbo & LeFevre, 2009).

Figure 11.5 Twelve or Two-Teen? As this graph shows, the percentage of American children who can count through the cardinal numbers drops off suddenly when they hit the number 11, whereas the percentage of Chinese children shows a more gradual decline (Miller, Smith, & Zhu, 1995)