Mathematics
Addition & Subtraction
Procedural
6–7 yrs
Adding and subtracting tens mentally
整十数的心算加减
Description
Add and subtract a two-digit number and tens mentally and using concrete/pictorial representations
Mastery Evidence
- Calculate 45 + 30 = 75 mentally
- Calculate 82 − 40 = 42 mentally
- Explain that only the tens digit changes when adding/subtracting tens
Assessment Prompt
Can your child quickly work out '54 + 30' or '78 − 20' in their head — knowing that only the tens digit changes?
