角的度量（9岁以上）
Measuring angles (age 9+)
认识角度的可加性；能在图形中利用含有未知数符号的等式，通过加法或减法求出未知角度。
Recognise angle measure as additive; find unknown angles by adding or subtracting on a diagram using equations with a symbol for the unknown
学习证据 / Evidence
- 一条直线上的两个角分别是65°和x°，求出x = 115°。
- 一个角被分解成35°和40°，说出整个角是75°。
- 求：同一个点处的角分别是120°、90°和x°，求出x = 150°。
- Two angles on a straight line are 65° and x°; find x = 115°
- An angle is decomposed into 35° and 40°; state the whole angle is 75°
- Solve: angles at a point are 120°, 90°, and x°; find x = 150°
评估问题 / Assessment
如果两个角紧挨着组成一条直线，其中一个角是65°，已知平角上的角总和为180°，{{name}}能算出另一个角是多少度吗？
If two angles sit next to each other on a straight line and one is 65°, can {{name}} work out the other angle — knowing that angles on a straight line always add up to 180°?