Things like addition and multiplication, which we saw not only apply to numbers, but we can use them on things like strings and we're going to come back to them again.

就像加法和乘法，我们已经学习过，它们不仅仅可以应用于数字，还可以用到字符串上,我们今天还会再讲讲。

麻省理工公开课 - 计算机科学及编程导论课程节选