Question

C an somebody please tell me what 9+10 is?

Answer 1

' 9 + 10 ' is a simple exercise in addition.  Its solution is  19 .

There is junk floating around the internet saying that 9+10=21.
That statement is false, and the arithmetic is wrong.
The whole thing is a joke.  If you ask someone to prove it, they will
perform a demonstration with Roman numerals, but the way they handle
the Roman numerals is itself defective, and they're hoping you won't notice.