Children’s performance on number line tasks reflects their developing number system knowledge. Before 5 years of age, most children perform poorly on even the simplest number lines (i.e., 0–10). Our goal was to understand how number line skills develop before formal schooling. Chilean preschoolers attempted a 0–10 number line task three times over 2 years: at the beginning of pre-kindergarten (M = 4:7 [years;months]; Time 1), at the end of pre-kindergarten (M = 5:0; Time 2), and at the end of kindergarten (M = 5:10; Time 3). We used latent class analysis to group children according to their patterns of performance across number targets. At Time 1, 86% of children had error patterns indicating that they randomly placed estimates on the line. At Time 2, 56% of children continued to respond randomly. At Time 3, 56% of children showed competent performance across the number line, 23% were accurate only near the endpoints, and 21% were accurate only for low target numbers near the origin. Latent transition analyses showed that the transition from less to more proficient estimation classes was predicted by children’s number identification skills. Thus, number line performance changed dramatically from 4 to 6 years of age as children began to develop the cognitive and numerical skills necessary to accurately estimate numbers on a number line.

孩子们在数轴任务上的表现反映了他们发展中的数系统知识。在 5 岁之前，即使是最简单的数轴（即 0-10），大多数儿童的表现也很差。我们的目标是了解在接受正规教育之前如何发展数列技能。智利学龄前儿童在 2 年内尝试了 3 次 0-10 数字线任务：在幼儿园开始时（M  = 4:7 [年；月]；时间 1），在幼儿园结束时（M  = 5 :0; 时间 2), 并且在幼儿园结束时 ( M = 5:10; 时间 3)。我们使用潜在类别分析根据儿童在数字目标上的表现模式对他们进行分组。在时间 1，86% 的儿童有错误模式，表明他们随机将估计值放在线上。在时间 2，56% 的儿童继续随机响应。在时间 3 时，56% 的儿童在数轴上表现出色，23% 仅在终点附近准确，21% 仅对起点附近的低目标数字准确。潜在转变分析表明，从较少到熟练估计班级的转变是由儿童的数字识别技能预测的。因此，随着儿童开始发展准确估计数轴上数字所需的认知和数字技能，数轴性能从 4 岁到 6 岁发生了巨大变化。