So I’m walking around in one of my classrooms, and this girl is doing binomials.

(x^2 – 2x – 15)

Okay, so we know the answer is (x+3) (x-5), but this girl had the signs mixed up for many of her answers, and she was rewriting them on her homework. Plus for minus, and minus for plus. So I’m looking over her shoulder, and I ask

Me: Hey, so what’s going on here?

Girl: Ooh I just got these signs wrong, I mixed it up.

Me: …so…what happened, do you understand it now?

Girl: oh, yeah, if they are both negative in the question, then the answer will have a negative and positive, I forgot and made them both negative…

Me: …..(wth…)…so wait, you’re just looking at the signs to determine what the signs in the answer will be?

Girl: Well, yeah, that’s what our teacher told us…

Me: (….what kind of lame cheap shortcut is this teacher teaching?) So, you understand that you have to find two numbers that multiply to the 3rd number, but add up to the 2nd number right? -5 and +3 multiply to -15 but add up to -2, that’s why you use those signs, not because of just memorizing how they should be. You should know why they are like that…

Girl: …….mm..yeah…

Me: You can also check your work by foiling again to make sure you get the right numbers too…then you’ll know for sure you have the right signs…

Girl:…well..yeah..i mean…but our teacher told us we could just do it like this…

And that, my friends, is why I get depressed working at schools sometimes. But! I’m glad I got to snap some of these kids out of it. You know some kids aren’t even writing their math homework correctly, working horizontally instead of vertically? With lines written haphazardly in different areas of the paper? It kills me when I see it and it makes it hard for me and the student to follow. Did no one teach them an organized and logical way to do their math? Grrrrrrr…I’m dedicating a lesson to how to write in good math format when I’m a teacher.