Howdy,
You are not the only one that this happens to. Many students face the same problem of making small errors. Most times these errors are even more frustrating because you understood the concept, you thought through the problem and planned your attack, and you felt confident that you were doing everything right. That's why we call them silly, stupid mistakes.
You can correct these errors, though. And honestly, to really break into the higher scores, you have to eliminate them completely. To do so, ask yourself where the error happens. Did the mistake happen at the end of the problem or at the beginning? Many times I see students make errors right at the end of the problem. It's natural for it to happen. How many times have we seen a team winning an entire game only to lose in the final minutes or a runner ahead in the race who loses in the final stretch? This all comes from the same tendency: we drop our guard when we see the finish line. We relax. We drop our focus. We rush. All of which does not help us to succeed. This human tendency to let up at the end has to be combated.
So when you are close to the end of a question, re-double your focus. Don't rush forward to finish quickly.
I hope that this helps a little bit!
Cheers!
