"Why do you put a wrong answer ever so often on your math homework?"

At my son's school, math homework consists of a chapter a night from the Saxon (old series) math book. He is in book 7 which I think is roughly 6th grade work. He is in 5th grade. He never shows his work and puts only the answers down in tight rows/columns (thought not necessarily neatly!). So- this means he is doing it in his head. I cannot do most of it in my head. When checking his work, we noticed he will ever so often put a random number down that is obviously not the correct answer- not even in the form required. So- my hubby asked him one day why he did that. His reply "well you only have to get 80% o nthe homework to be able to take the test on Friday. The test is what is graded. If it is too much of a hassle to figure out and I am pretty sure I got the others right, I just choose to miss that one."

My question- what is the school teaching my son? Certainly not math! How can one bring that to the teacher and not make him/her look like an idiot? At least you would hope they would feel that way. My expereince tells me the teacher would make up some sort of rational as to why he still needs to do work that is not challenging. My favortie is "What if he gets into higher level math and is missing some pre-requsites?" Hmm-well if that happens, I bet he will just go research it and figure out what he needs to know. Probably with out a teacher's assistance.

sigh...