I don't teach to the test but I do teach test taking skills. Although I want the kids to know and understand the math, the bottom line is all most care about is their grade.
We just finished a unit on differential equations and with every questions I stress the importance of "plus C", emphasizing that the readers will not even look at their work if they leave that out. One of my kids just posted the following on our Facebook page. I'm really going to miss this group.
Two math professors are sitting in a pub.
"Isn't it disgusting", the first one complains, "how little the general public knows about mathematics?"
"Well", his colleague replies, "you're perhaps a bit too pessimistic."
"I don't think so", the first one replies. "And anyhow, I have to go to the washroom now."
He goes off, and the other professor decides to use this opportunity to play a prank on his colleague. He makes a sign to the pretty, blonde waitress to come over.
"When my friend comes back, I'll wave you over to our table, and I'll ask you a question. I would like you to answer: x to the third over three. Can you do that?"
"Sure." The girl giggles and repeats several times: "x to the third over three, x to the third over three, x to the third over three..."
When the first professor comes back from the washroom, his colleague says: "I still think, you're way too pessimistic. I'm sure the waitress knows a lot more about mathematics than you imagine."
He makes her come over and asks her: "Can you tell us what the integral of x squared is?"
She replies: "x to the third over three."
The other professor's mouth drops wide open, and his colleague grins smugly when the waitress adds: "...plus C."