分数、小数与百分数

寻找并运用数学结构：利用分数、小数与百分数之间的关系；用因数对简化乘法；用角度关系求未知数；系统地运用正多边形的性质。

Look for and use mathematical structure: exploit the relationship between fractions, decimals, and percentages; use factor pairs to simplify multiplication; apply angle facts to find unknowns; use properties of regular polygons systematically

学习证据 / Evidence

• 利用因数对，按 25 × 16 = 25 × 4 × 4 = 100 × 4 = 400 的结构进行计算。
• 认识到 0.75 = 3/4 = 75%，并根据题目选择最有效的形式。
• 利用“一条直线上的角之和为 180°”这一事实，作为求未知角的结构工具。

• Use the structure 25 × 16 = 25 × 4 × 4 = 100 × 4 = 400 by exploiting factor pairs
• Recognise that 0.75 = 3/4 = 75% and use whichever form is most efficient for the problem
• Use the fact that angles on a straight line sum to 180° as a structural tool to find missing angles

评估问题 / Assessment

当{{name}}意识到分数、小数和百分数只是同一个数的不同写法时，他们会利用这一点，在能让计算更简便时灵活地相互转换吗？

When {{name}} notices that fractions, decimals, and percentages are just different ways of writing the same thing, do they use that understanding to switch between them fluidly when it makes a calculation easier?