Assumption

In Section B, the marks in the calculation parts of questions are for each step of the workings. If you are doing it the correct way, then you still get the marks even if some of the figures are wrong. So if you do hit a problem then if needed 'invent' a figure so that you can still continue and prove that you know the correct approach. In Section A (where your workings are not looked at) if you cannot do a question then you should guess an answer. You might be lucky and guess correctly and therefore get the marks :-)

Thank you sir

You are welcome :-)