加法和减法
Adding and subtracting
能计算一位数和两位数到20以内的加减法，包括与0的加减。
Add and subtract one-digit and two-digit numbers to 20, including zero
学习证据 / Evidence
- 计算 14 + 5 = 19
- 计算 17 – 3 = 14
- 进行加0或减0的运算，并说明结果保持不变。
- Calculate 14 + 5 = 19
- Calculate 17 – 3 = 14
- Add or subtract 0 and explain the result stays the same
评估问题 / Assessment
{{name}}能心算或在纸上算出像“14 + 5”或“18 − 6”这样的算式吗？他们知道加0或减0后数字保持不变吗？
Can {{name}} work out sums like '14 + 5' or '18 − 6' in their head or on paper, and do they know that adding or taking away zero leaves the number unchanged?