"Show your calculation" in the AM

What do you think - is this a partial credit opportunity if you for example forget to adjust return for inflation, or they want to make sure candidates do not glance at results from other candidates because it would be easy to do so?

This is absolutely a partial credit opportunity.

IMO then iIt could be tough for the grader to conclude how much partial credit to give.

Imagine this required return on portfolio scenario. I usually write down just PV, FV, PMT, N and then calculate I/Y. After that if necessary I make adjustments for inflation and taxes. I do not write how I got my PMT, which could for example be the shortfall of pension income against living expenses. Now imagine someone who writes everything down. Pension income, tax adjustment, total assets, total outflows for say education purposes and so on. This would take quite a lot of time.

How do you approach these show your calculation problems. Do you write as little calculations as necessary (the way I do) or you go as described?

If it’s a basic IRR calculation most of the inputs would be given in the question so you would just write those variables next to N, i, etc.

If there’s a calculation involved to get PMT I would write those in (+100,000 income - $150,000 expenses = -$50,000 PMT). You don’t want to waste too much time here but at least the grader will see where you’re getting your numbers. If you mixed up a calculator input (using negative instead of positive) perhaps they’ll be lenient and give you partial marks.