Mathematics
Addition & Subtraction
Conceptual
6–7 yrs
Finding a missing number in addition
加法中的缺失数
Description
Understand subtraction as finding an unknown addend (e.g. 10 − 8 = ? is the same as 8 + ? = 10)
Mastery Evidence
- 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
Assessment Prompt
Can your child 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?
