You can approach most complex problems from various angles. Each one might give you an approximate answer; by comparing these you can estimate the overall answer.
Approach your problem from different angles
When I interviewed to join Accenture, I went through a series of case interviews. If you’ve heard of strategy consulting, you’ve most certainly have heard of these: the interviewer asks you a seemingly complicated question and wants you to show him/her how you get to the answer. Traditional case questions include: how many golf balls can you fit in a Volkswagen? How many gallons on white paint are sold yearly in the US to paint residential houses? How much does it cost to run a (successful) presidential campaign? Etc.
