' 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.
I have always followed an easy rule: "five or more raises the score". What it means is if the number is 5 or more, it goes to the next whole. Make sense?
