组合图形的面积
Area of compound shapes
理解面积是可加的；能将直边图形分解成若干个不重叠的长方形，分别算出面积再相加，从而求出整个图形的面积。
Recognise area as additive; find areas of rectilinear figures by decomposing into non-overlapping rectangles and summing their areas
学习证据 / Evidence
- 把一个 L 形分解成两个长方形，分别求出面积再相加
- 把一个 T 形平面图分割成几个长方形，求出它的面积
- 解答：一间 L 形房间（3米×5米加上2米×4米）的总面积是多少？
- Decompose an L-shape into two rectangles, find each area, and add them
- Find the area of a floor plan shaped like a T by splitting into rectangles
- Solve: A room is L-shaped (3m×5m plus 2m×4m) — what is the total area?
评估问题 / Assessment
如果给{{name}}一张方格纸，上面画着一个 L 形房间，{{name}}能把它分成两个长方形，分别求出每部分的面积，再相加得到总面积吗？
If {{name}} is given an L-shaped room on squared paper, can they split it into two rectangles, find the area of each part, and add them to get the total area?