十几的数

理解十几的数（11–19）由一个十和几个一组成（初步的位值概念）

Understand that the teen numbers (11–19) are composed of ten ones and some further ones (early place value)

学习证据 / Evidence

• 用物品把14组成一个十和四个一
• 把17分解成10+7并记录成等式
• 解释13是“一个十和三个一”

• Compose 14 as a group of ten and four ones using objects
• Decompose 17 into 10 + 7 and record as an equation
• Explain that 13 is 'one ten and three ones'

评估问题 / Assessment

如果{{name}}有14块积木，ta能把它看成一个完整的10块积木塔和剩下的4块吗——从而理解“十几”的数就是十加几？

If {{name}} has 14 building blocks, can they see it as one full tower of 10 and 4 left over — understanding 'teen' numbers as ten-and-some-more?