When buying things at the self-checkout machine (at a well-known store named Wal-Mart), the self-checkout machine might say the following to me:
Votre total est de dix dollars.
(It says this verbally; that is, without text on the screen. This is my best guess about what it is saying).
My question is about the "de". No grammar understanding that I currently have lets me know what the "de" is for.
On wordreference, the webpage for "être de" does not seem to help. The closest thing is that there is an entry for "être à (prix)".
1) What is causing the "de" to be there? Are there similar sentences that can exist, that also have a "de" for a similar reason, or is it only for "Votre total est de"?
2) Would it be correct French to say "Votre total est dix dollars"?