A curveball question to put a candidate on the spot
No calculator, pen or paper permitted. What is 49 squared?
This is the question I ask interviewees at Clear Books. I particularly like this question because someone asked me the same question in an interview when I was at KPMG so I can benchmark against my own response.
It’s great for putting the pressure on, seeing if the candidate can do some sums in their head and also if they can think logically to simplify the problem.