Organizing math

case math
New answer on Aug 02, 2021
4 Answers
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Anonymous A asked on Aug 01, 2021

What's the best way to keep your math organized? Draw tables? Any other tips?

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Sofia
Expert
updated an answer on Aug 01, 2021
McKinsey San Francisco | Harvard graduate | 5+ years of coaching | >90% candidate success rate | Personalized approach

Hello! I wholeheartedly agree with all the great tips Erica has shared in her answers. Here are a few more I would add:

1. The specific method you use doesn't matter as long as the math is organized - so do what works best for you! When I interviewed, my preferred method usually involved writing out simple equations (e.g. P x Q = Revenue, and then substitute the specific numbers below that), but tables would work equally well. As long as the method is quick to write up, relatively clean, and simple to explain, you should be good to go.

2. That being said, be flexible, and try to adapt your process to the case at hand. In some cases, a table would be the cleanest and most obvious solution, whereas in other cases jotting down some numbers or even sketching a graph could be more appropriate. Experiment with different methods in your case prep to understand what works well for which style of question (or work with a coach to get some useful feedback on this), and always try to use the most straightforward method given the question.

3. Regardless of what method you use, make sure to clearly explain what you are doing to the interviewer. Again, the specific method you use doesn't matter as long as it's clear to the interviewer, but a process that feels like second nature to you after all the case prep you've done might look confusing or unfamiliar to an someone seeing it for the first time, so be sure to take your interviewer through each step of your work. You could do this as a voiceover while you are drawing up your table (or its equivalent), or quickly draw first and then recap what you drew second, but saying something like "Here I have organized the numbers in a table, with XYZ in the first column and ABC in the second column..." could be helpful to make sure the interviewer is following along.

4. To echo Erica's point, if you are someone (like me!) whose natural way of solving math problems is with messy scribbles and sums all over the page, I would recommend keeping that work separate from the "neat" math you present to the interviewer. You could even draw a line on the page (e.g. at the 1/4 page point) to set up a "rough work" section to make sure it doesn't bleed into your other notes.

5. If you are allowed to use your own scrap paper in the interview (which will generally depend on the firm and interview stage), you could bring graph paper to help draw more organized tables and graphs.

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Erica
Expert
Content Creator
updated an answer on Aug 01, 2021
Ex-McKinsey / 100% offer rate / LBS / Principle driven / Real case/ If you get the interview, you should get the offer!

Hi there. There are several things you can do in terms of notes-taking and thinking process. I'm listing them as below.

Notes-taking

- Divide your maths notes into two parts. One part is for the "clean stuff", meaning your formula, key numbers, final results, insights drawn from the numbers, etc. Basically anything that you can communicate and present. Second part is for you to do all your "doodling"/calculation. 

Thinking process

- Do a backward deduction. For example, if you're asked to calculate next year's revenue, you can think "in order to calculate the revenue, I would need to know A and B, and in order to know A, I need A1, A2, A3, etc" 

- Ask interviewer for numbers only after you work out your process/method. In this way you won't get confused if given big amount of data and you won't miss any key numbers if not provided (sometimes interviewer forget!)

Hope this helps!

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Agrim
CoachingPlus Expert
replied on Aug 02, 2021
ex-BCG Dubai PL | 100% Personalised Coaching | 2021 Real Cases only | 6+ years in Consulting

Hi there!

Your recipe is usually your own. I would suggest to keep practicing to develop your own flow.

Do share your workings with your coaches to get very specific feedback on how to go about the organization of your math.

You can also check out my answer to this question that can have some relevant ideas for you - https://www.preplounge.com/en/consulting-forum/improving-case-flowmath-10988

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Ian
Expert
Content Creator
replied on Aug 02, 2021
BCG | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi,

Use tables for multi-dimensional data.

If the interviewer gives you linear data, you can simply jot it down on the LHS. However, if they say, for example "We have 4 main costs", you better be setting up a table ASAP! Those 4 costs will be your rows, and any additional information given will be in each respective column.

Not only will this help you write down all of the information quickly AND keep track of it, but it will help you figure out where to go next!

By the way, the same applies for exhibits. Write down the key information back onto your sheet!

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Sofia gave the best answer

Sofia

McKinsey San Francisco | Harvard graduate | 5+ years of coaching | >90% candidate success rate | Personalized approach
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