选择合适的策略

能够策略性地选择和运用合适的工具与表示方式，包括在多位数、小数和分数的计算中，按照需要选择心算、草稿演算、规范算法或计算器。

Select and use appropriate tools and representations strategically, including choosing between mental methods, jottings, formal algorithms, and calculators for arithmetic with multi-digit numbers, decimals, and fractions

学习证据 / Evidence

• 对于345 + 200会选择心算，但对于345 + 278会选择笔算。
• 会根据要测量的物体，选择用直尺还是米尺。
• 能判断在解决某个问题时，什么时候用数轴比用十进制位值积木更有用。

• Choose a mental method for 345 + 200 but a written method for 345 + 278
• Select a ruler vs a metre stick based on the object being measured
• Decide when a number line is more useful than base-ten blocks for a given problem

评估问题 / Assessment

当{{name}}遇到数学问题时，会不会想一想哪种方法最合适——比如简单的题心算，较大的计算用笔算，几何题画个示意图？

When {{name}} faces a maths problem, do they think about which method suits it best — like doing easy ones in their head, using a written method for bigger calculations, or sketching a diagram for geometry?