Let's is a contraction of “let us,” used when you want to invite someone to do something with you. When you say “Let's play outside,” you're suggesting that you and your friend (or friends) do something together.

The word carries a spirit of togetherness and shared action. It's the difference between commanding someone (“Go clean your room”) and inviting them to join you (“Let's clean up together”). When a teacher says “Let's begin,” she's including herself in the activity, signaling that everyone is working together.

People use let's for all sorts of suggestions: “Let's try this new strategy,” “Let's see what happens,” “Let's grab lunch.” The phrase makes suggestions feel friendlier and more cooperative. If your brother is struggling with homework, saying “Let's figure this out” sounds more helpful and encouraging than “You need to figure this out.”

You might also hear “Let's not” when someone wants to suggest avoiding something: “Let's not argue about this.” The contraction works because it turns a somewhat formal phrase (“let us”) into something casual and natural that people actually say in everyday conversation.