How do I simultaneously show my thinking while also calculating during the math section?

Hi there,

1) How do I simultaneously show my thinking while also calculating during the math section?

You don't need to do both at the same time. Ideally, you should first present the approach and then do the math.

2) Should I start going stream of consciousness by telling them what I'm doing? Or should I just do all this in my head and then once I'm done I explain to them what I was doing & how I did it? 

I would not recommend any of the two extremes. No need to say aloud everything single math step or just the final result. 

Instead, after you have presented your approach, you can guide the interviewer through the main intermediate math steps to get the final result, so he/she is aligned with you.

Additionally, you don't need to do the math in your head, you can write it down without any issue, unless the interviewer explicitly asks for that.

In terms of how to approach a math problem, this is what I would recommend:

1. Repeat the question – sometimes candidates do mistakes answering the wrong question
2. Ask for time and present the formula/approach you would like to use
3. Start doing the math and present the interim math steps to keep the interviewer aligned – don’t just say the final number
4. Continue with the math until you get the final answer
5. Propose next steps based on the results you found

Best,

Francesco

In addition to Ian's good suggestions, I will just add a bit more context from the interviewer's POV:

1. As an interviewer I am testing if you are not only comfortable with numbers but can think and reason quantitatively 

• Anecdotally, I have had many friends who have gone through MBB interviews where after they have laid out their math structure (well), the interviewer had told them to skip the actual calculations
• On the job, when i was a case PL its far more practical and helpful to have a consultant on my team that can setup / structure the quant well. Excel (or tableau etc) does the actual calculations, and a poorly setup/structured/wrong formula will yield a poorer answer

2. Too much rambling/babbling can also easily make you sound ‘unstructured’, and is hard to follow for the interviewer

• ‘Answer first' is a phrase or term you might commonly hear
• Stating your math approach first is not exactly the same as the Pyramid Principle, but the concept is essentially saying “here is my approach and how I intend to solve this problem, now let me go and solve it”
• Versus your ‘stream of consciousness’ which is something like “i am solving this now this is step one i am solving this now this is step 2….."
• Its much harder for the interviewer to follow detailed calculations piecemeal, especially virtually, than for you to talk structure and approach (without numbers)
• On the job, similarly I used to expect most consultants under me to align on their broad approach before diving into the analysis and numbers. The risk otherwise is my consultants would go down the wrong rabbit hole

Hope this helps you to understand better some of the great advice Ian and other coaches may give you.

(editiert)

You don't.

1) State what you want to calculate and why

2) Say you want a moment to set it up

3) Clearly articulate your math approach

4) Go and do the math (but pop your head up with “key” numbers)

Please don't blabble about with every single math calc :)

Hi there,

The best practice formula for case math questions is:

Always split the thinking from the talking from the calculating.

Whenever you do 2 or 3 at the same time you significantly increase the risk of errors.

In practice:

1. Play back the numbers (talking)
2. Think about your approach for 1 minute (thinking)
3. Discuss your approach with the interviewer (talking)
4. Calculate and sanity check your outcome (calculating)
5. Present the result to the interviewer (talking)
6. Interpret it in the context of the case and discuss how to move forward (talking)

If you combine steps 2 and 3, you might blurt out a wrong approach and once it's out the interviewer has noticed it. If you calculate out loud and make a mistake, the same issue, etc.

Case interviews are also about being confident when taking time to properly think through problems and let the other person wait/sit in silence.

Cheers,
Florian

Hi there,

I think this is an interesting question that may be relevant for many people. I would be happy to share my thoughts on it:

• When it comes to quantitative questions, it is not necessary to show your thinking and perform calculations at the same time. It is better to first present your approach, and then proceed with the math.
• Moreover, instead of communicating every single step or simply presenting the final result, I would advise you to guide the interviewer through the key intermediate steps as you perform the calculation. This way, the interviewer can stay aligned with your thought process. Writing down the calculations can also help, unless the interviewer specifically requests otherwise.

If you would like a more detailed discussion on how to address your specific situation, please don't hesitate to contact me directly.

Best,

Hagen

You should:

1. Explain how you plan to do your analysis

2. Do the calculations

3. Present the result in the context of the implications for the recommendation / case objective. 

So you don't do it at the same time. You do it in sequence - otherwise you are just being unstructured in your communication.

Hi there,

I've developed a guide that explains just that. Happy to share it for free. Just reach out via a DM. 

In short, you need to look at 4 steps when you approach a calculation questions. 

1. Validate the data, the questions and read the exhibit with the interviewer (if given one). The point here is to just understand what it is that you need to solve for, what is the data that you have available and what is the composition of the data. Then ask for time and take somewhere up to 30s. 

2. Come up with a step by step, end to end approach and share it with the interviewer. At this point don't even touch the numbers. Just come up with the logic that you would need to get to the result. Take the interviewer through it and if they have any feedback adjust your approach to integrate their thoughts. Then ask for a few seconds of time again to do the computations on your own and to sanity check them. 

3. Take the interviewer through the calculation steps in the same order as when you presented them the logic earlier (now with actual number plugged in). Do this until you get to the final result and the interviewer confirms it. 

4. Then interpret the result. Discuss what number you arrived at tells us about the client situation and what consequences it has. It's the moment in the case when you get to ‘connect the dots’. 

That's about it!

Best,

Cristian

Coach Ian is spot on! Its very difficult if not impossible to think, calculate and speak at the same time.