周长（10岁以上）
Perimeter (age 10+)
认识面积相同的图形周长可能不同，周长相同的图形面积也可能不同，并系统地探索这种关系。
Recognise that shapes with the same area can have different perimeters and vice versa; explore this relationship systematically
学习证据 / Evidence
- 画出两个面积都是24平方厘米但周长不同的长方形。
- 找出两个周长都是20厘米但面积不同的图形。
- 解释为什么一个细长的长方形和一个正方形可以有相同的面积但周长不同。
- Draw two rectangles with area 24 cm² but different perimeters
- Find two shapes with perimeter 20 cm but different areas
- Explain why a long thin rectangle and a square can have the same area but different perimeters
评估问题 / Assessment
如果{{name}}有12块正方形瓷砖要排列，能摆出不同形状的长方形，并注意到面积始终相同（都是12块瓷砖），但周长各不相同吗？
If {{name}} has 12 square tiles to arrange, can they make different-shaped rectangles and notice that the area stays the same (12 tiles) but the perimeters are all different?