And it is equal to the sum of the number of protons plus the number of neutrons.

它等于质子数,加上中子数。

麻省理工公开课 - 固态化学导论课程节选

And what's important to keep in mind about formal charge is if we have a neutral atom, such as we did in thionyl chloride here, the sum of the individual formal charges on individual atoms within the molecule have to equal 0.

而关于形式电荷记住一点是很重要的,那就是如果我们有一个中性原子，比如亚硫酰氯，那么这个分子中的所有原子的,形式电荷之和应该等于零。

麻省理工公开课 - 化学原理课程节选

It is clear that that vector is the sum of that vector and that vector, by the rules of vector addition, because that plus that is equal to the A.

这个矢量是这个两个矢量之和,根据矢量加法的法则,因为这两个矢量相加就等于 A

耶鲁公开课 - 基础物理课程节选