Have you ever heard of an Error Carried Forward?
Way back in the early 90s, I was in college for Nuclear Engineering. One of my favorite classes (at the time) was "Atomic Physics." The ex-Navy Nuke Instructor we had was quite interesting in his own right (that's a different story), and one day I got a test score back that had "ECF" written on the top of the page. Apparently, I wasn't the only one with this on my exam, because other students were asking what "ECF" meant.
Come to find out that we were given a break that you don't often get in the real world: error carried forward. The terminology means that if you make a mistake early on in the math, than you have still have a chance to show the evaluator that you understand some of the process, because the instructor will follow the incorrect answer through your process and still give you credit for getting the concept and applications correct.
An error waiting to be discovered
I imagine you can see this resembles the Human Performance definition of a latent error. If the evaluator only looked at the end product, the results may never be correct and the individual would always fail, but if the evaluator looks at the entire system, they should be able to find the flaws and uncover the barrier that broke. In this case, when the math got goofy. As a trainer, I have to say I really appreciate anyone who takes the time to use the ECF process as to support and not discourage students who are trying their hardest. It certainly represents extra work on the instructor's part.
Smaller than an atom
I also remember another note this same teacher put on an exam score of mine referring to the remaining particle being outrageously smaller than the size of an electron. He wrote, "You're going to need a sharp knife" with no explanation - presumably to cut an electron into impossibly tiny parts to fit my math. In case it isn't clear, I may have finished that college degree program, but was never truly an engineer because of a love/hate relationship between me and the math.