bill or invoice

[Ungifted]

What is correct answer #a, answer #b or both answers?
What do I have to pay?
a. The bill is exactly $10.
b. The invoice is exactly $10.

 

[SoothingDave]

What is the context?

Bill is more informal and used in everyday situations (like paying the bill at a restaurant).

An invoice is associated with either the paperwork that accompanies a shipment of goods, or the document sent from a company demanding payment for goods or services.

 

[Rover_KE]

Note that '#' is used to mean 'number', so it doesn't go before a letter.