As you build these kinds of simulations, or anything like this, you need to think through whether things should be multiplicative or additive.

正如你建立各种仿真程序，或者类似的仿真程序时，你应该去想一想,他们应该是用加法还是用乘法。

麻省理工公开课 - 计算机科学及编程导论课程节选