In fact, there are some very old books that show this as the average, the sum divided by two arithmetic mean, but the modern practice is to use the geometric mean.

事实上，一些很老的书籍上,平均的定义就是算数意义的，总的来说被分为两种算数意义，但现代我们多用几何意义。

麻省理工公开课 - 固态化学导论课程节选

I just want to make mention of this in case there's ever doubt, generally parentheses do solve your problem as an arithmetic but do realize this is some lower level details we'll come back to over time.

是想告诉大家如果你对某些式子的前后运算关系不确定，就加上括号,这都是一些小细节,我们以后还是会再提到的。

哈佛公开课 - 计算机科学课程节选

The truth is after this, it's all arithmetic, right?

真理在这之后，它全是些算术？

麻省理工公开课 - 热力学与动力学课程节选