加法中求未知加数

理解减法就是寻找未知的加数（例如：10 − 8 = ? 等同于 8 + ? = 10）。

Understand subtraction as finding an unknown addend (e.g. 10 − 8 = ? is the same as 8 + ? = 10)

学习证据 / Evidence

• 用“8加几等于10？”的想法来算出10 − 8。
• 能解释减法可以看作求未知加数的问题。
• 能利用已知的加法算式来解决相关的减法问题。

• Solve 10 − 8 by thinking 'what do I add to 8 to make 10?'
• Explain that subtraction can be thought of as a missing-addend problem
• Use known addition facts to solve related subtraction problems

评估问题 / Assessment

{{name}}能否看出“10 − 8 = ?”其实就是在问“8加几等于10？”——从而能运用自己学过的加法知识来帮助解决减法问题？

Can {{name}} see that '10 − 8 = ?' is the same as asking 'what do I add to 8 to reach 10?' — so they can use their adding knowledge to help with subtraction?