任意顺序相加
Addition in any order
理解并应用加法交换律:加数可以按任意顺序相加
Understand and apply the commutative property of addition: addends can be added in any order
学习证据 / Evidence
- 说明3 + 8和8 + 3的答案是一样的
- 利用交换律,选择从较大的数开始往后数
- 说明减法不满足交换律(5 − 3 ≠ 3 − 5)
- Explain that 3 + 8 gives the same answer as 8 + 3
- Use commutativity to choose the larger number to count on from
- Demonstrate that subtraction is not commutative (5 − 3 ≠ 3 − 5)
评估问题 / Assessment
{{name}}是否知道6 + 4和4 + 6的答案一样,因此他们总是可以选择更方便计算的顺序来相加?
Does {{name}} know that 6 + 4 gives the same answer as 4 + 6, so they can always choose whichever order makes the adding easier?