## What is the interviewer looking for?

In estimation interview questions, interviewers are evaluating your problem-solving and quantitative skills. They are looking for a ballpark number, not an accurate number. What matters is whether you are logical, can explain all your assumptions clearly, are organized in your work, and good with numbers.

## How to structure your answer?

The book *Cracking the PM Interview* by Gayle Laakmann McDowell and Jackie Bavaro provides a good suggestion on how to structure an answer for this type of question. It can be summarized as:

**Ask clarifying questions**. This will eliminate any ambiguity of what should be included in your calculations.**Make an equation**. Consider edge cases or alternate sources of data and write down any facts that you know will help with calculations.**Break down the equation into components**. Write down any assumptions next to the components so you donâ€™t forget to explain them clearly to the interviewer.**Do the math**. Calculate the result of each component and compute the result.**Do a sanity check**. Do your results make sense? If not, recheck your equation, assumptions and arithmetic.