乘以整十数
Multiplying by Tens
运用基于位值和运算性质的策略，计算一位整数与10–90之间的整十数的乘法。
Multiply one-digit whole numbers by multiples of 10 in the range 10–90 using strategies based on place value and properties of operations
学习证据 / Evidence
- 通过推理计算 7 × 30 = 210：7 × 3个十 = 21个十 = 210。
- 解释为什么乘以整十数会在积的末尾添一个0。
- 运用这一技能来估算较大数的乘积。
- Calculate 7 × 30 = 210 by reasoning 7 × 3 tens = 21 tens = 210
- Explain why multiplying by a multiple of 10 adds a zero to the product
- Use this skill to estimate products of larger numbers
评估问题 / Assessment
{{name}}能先算一位数乘法，再在末尾添上0，快速算出“7 × 40”或“6 × 80”，得到280和480吗？
Can {{name}} quickly work out '7 × 40' or '6 × 80' by first doing the single-digit multiplication and then placing the zero — getting 280 and 480?