乘法的符号规则

用正整数、负整数和有理数进行乘法和除法，理解积或商的符号判定规则。

Multiply and divide with positive and negative integers and rational numbers, understanding the rules for the sign of the product or quotient

学习证据 / Evidence

• 运用符号规则计算两个整数的乘法（正数乘负数、负数乘负数）
• 运用符号规则计算两个整数的除法
• 解决涉及正、负有理数四则运算的多步现实问题

• Apply the sign rules when multiplying two integers (positive × negative, negative × negative)
• Apply the sign rules when dividing two integers
• Solve multi-step real-world problems involving all four operations with positive and negative rational numbers

评估问题 / Assessment

如果{{name}}知道“负负得正”，能否运用这一规则计算像“−3 × −4 = 12”这样的算式，并解释其中的道理？

If {{name}} knows that a negative times a negative makes a positive, can they use that rule to work out calculations like '−3 × −4 = 12' — and explain why it makes sense?