Day

As the second person in the dialogue, you would say use "mine".

pleasehelpI had a great day!

How was yours?

Can I answer with yours?

Your formatting makes it unclear what you're asking. I assume it's this:

If someone says, "I had a great day! How was yours?" can I respond, "Yours"?

The answer is no. That would make no sense whatsoever. Respond

Sorry I meant:

Can I say How was yours. Or would I have to use:

How was your day?

Thanks

pleasehelpCan I say How was yours? Or would I have to use:

How was your day?

After you have answered how your day was, you can certainly ask, "How was yours?"

Yes.

CJ