A further comment:
You all started off fine on Q.1. But then there’s a pattern. On the whole your work gets more random and scrappy towards the end of the paper.
It’s not an absolute rule. Some of you messed up an earlier question then did fine on a later one. But it’s a trend.
With a lot of you, it looks as if the first time you ran into difficulty – usually not because you didn’t know the basic method, but because you made a slip in calculation – that broke your confidence, and then your work became scrappier and scrappier.
I suggest two counter-measures.
1. At the start of any test, read through the whole paper and mark each question according to how easy it looks. Then do them easiest first. Don’t just start with Q.1 and plod on towards the end.
2. If you find you are running into difficulties on a question, think: oh, I’ve probably made a slip somewhere. Have a quick look to find the slip. If you can’t find the slip quickly, leave that question, go on to the next easiest question, then come back later to look for the slip.