I have done every single edexcel past paper, and with the C1 exam 14 days away, I want to get at least 90% in that paper, however I am always averaging around 56-58/75 and generally I tend to loose out on 10 or so marks just from silly mistakes like integrating instead of differentiating (vice versa) or even messing up on simple calculations, for example in one paper I wrote 3 times 2 was 9. Any advice on how I can ace C1?