hi
do yourself a favour and DO NOT use a pencil for the CRP-5 work. In some questions you'll get the wrong answer due to the examiner being silly and placing answers 2 knots apart for example.
Use a fine tip red water based marker.you then simply brush over the mark with your thumb and move onto the next question. In general navigation time is very important and the last thing you want to do is rub out pencil marks and stare at a dull grey dirty CRP from previous work.
good luck