Is the following grammar correct:
The table with four chairs are discounted today.
no are should be were
I'd change are to is.
If you completely want to change that sentence, than you can say the following:
That table with four chairs surrounding it, is discounted today.
You could take the "surrounding it" it out, if you'd like.
Please note that are doesn't have to be changed to is, it could be changed to was, if you're talking about the past tense. If you're talking in the present tense then leave it as "is".
Anonymous is correct that since the subject is "table" (singular) the verb also needs to be singular -- is or are.
You could also write this, making the subject plural:
The table and four chairs are discounted today.
No, the grammar in the sentence is not correct. The error lies in the subject-verb agreement. In this case, the subject is "the table with four chairs," which is treated as a singular noun phrase. Therefore, the verb should also be singular.
To correct it, you can say:
"The table with four chairs is discounted today."
In this revised version, the singular verb "is" agrees with the singular noun phrase "the table with four chairs."