I assume the phrase "let's" is a shortened form of "let us." But since the word "us" is a plural form, could I only use it when there are multiple people around?

Native speaker’s answer
Rebecca
Yes, "let's" is a contraction of "let us." And you're right! It only works with more than one person. So it could be you and someone else, or you and a group of people. Ex: Let's get take out tonight. => 2 or more people Ex: Let's help Aaron with his project, and then we'll go home.