Oh the Irony

Define Irony,
come on, you can do it,
for those numbskulls who can't, let me give my own version of irony.

It was during math class yesterday. We were going through a revision paper the math teacher gave us. I got one of those algebra, "give away" as my teacher calls it, questions wrong.
It was because I forgot to change the signs after removing the brackets.
Example
6-(4+5) = 6-4-5
I wrote
6-(4+5) = 6-4+5

I'm not really good at algebra.
So the teacher asks, "Who got the question wrong?"
I honestly reply, "Me."
And she says," Well, serves you right for not paying attention during class."
I was flabbergasted
The ironic think is I pay attention in class and get questions like this wrong while the guy next to me doesnt pay attention and gets it right. I'm just new to algebra, teacher! I hate it when people tell me off for things I did not do. Well, this also be interpreted as "life is unfair" but I don't really think so. Even if it was, Deal with it!
You can call it a rant, but I'm just letting my frustration out.
Arrgh, Exams,
Kevin (no snide sarcastic comments, sorry)