Is it polite to say "let's all" after I answer a question?

[heyuting]

Is it polite to say "that's all" after I answer a question of a test?

Because someone told me that it's impolite to say "that's all" at the end of conversation.

Sorry, I make a mistake. What I want to say is "That's all" not "let's all"

[5jj]

I can't think of why anyone would want to say 'let's all'. What do you intend it to mean?

[emsr2d2]

I have never heard that phrase in my life. If you said it after you answer a question in a test or at the end of a conversation, I would say "Pardon?" or "Excuse me, what?!" or I would simply walk away very confused.

The only thing I can think that it sounds like is "That's all" but you wouldn't say that after answering a question in a test or at the end of a conversation either.

[Barb_D]

Let's all go out for a beer to celebrate finishing our exams?

[heyuting]

Sorry, I make a mistake. What I want to say is "that's all"

I can't think of why anyone would want to say 'let's all'. What do you intend it to mean?

[heyuting]

Haha, that's interesting.
I make a mistake. what I want to say is "That's all"

Let's all go out for a beer to celebrate finishing our exams?

[5jj]

I doubt if any native speaker would say 'That's all' in the situations you have described.

[heyuting]

You got me. Sorry to make that mistake. What I want to say is "That's all"
Thank you.

I have never heard that phrase in my life. If you said it after you answer a question in a test or at the end of a conversation, I would say "Pardon?" or "Excuse me, what?!" or I would simply walk away very confused.

The only thing I can think that it sounds like is "That's all" but you wouldn't say that after answering a question in a test or at the end of a conversation either.

[Barb_D]

As ems already said, that would be an inppropriate (if not puzzling) thing to say at the end of an exam or the end of a conversation.

If you're looking for a nice way to end a conversation, you can say "Well, it was nice talking to you." The other person will say "You too" and then you go your separate ways. Other things you could say, depending on the circumstances include "It was was nice meeting you" or "It was good seeing you again" or "I hope we get to see each other again soon" or "I'm so glad we got a chance to compare notes" or "Thanks for sharing your thoughts" or... many things. But not "that's all."

[heyuting]

Okay, I see. But can you tell me why? Impolite?
Thank you!

I doubt if any native speaker would say 'That's all' in the situations you have described.