心算三位数与整百数加减
Mentally adding hundreds to 3-digit numbers
心算三位数与整百数的加法和减法
Mentally add and subtract a three-digit number and hundreds
学习证据 / Evidence
- 心算 345 + 200
- 心算 762 − 400
- 解释只有百位数字会变
- Calculate 345 + 200 mentally
- Calculate 762 − 400 mentally
- Explain that only the hundreds digit changes
评估问题 / Assessment
{{name}}能不能不用纸笔，快速算出“342 + 200”或“756 − 300”，并知道这时只有百位数字会变？
Can {{name}} quickly work out '342 + 200' or '756 − 300' in their head — knowing that only the hundreds digit changes?