Cookie and Privacy Settings

This website uses cookies to enable essential functions like the user login and sessions. We also use cookies and third-party tools to improve your surfing experience on preplounge.com. You can choose to activate only essential cookies or all cookies. You can always change your preference in the cookie and privacy settings. This link can also be found in the footer of the site. If you need more information, please visit our privacy policy.

Data processing in the USA: By clicking on "I accept", you also consent, in accordance with article 49 paragraph 1 sentence 1 lit. GDPR, to your data being processed in the USA (by Google LLC, Facebook Inc., LinkedIn Inc., Stripe, Paypal).

Manage settings individually I accept
expert
Expert with best answer

Francesco

100% Recommendation Rate

3,275 Meetings

11,963 Q&A Upvotes

USD 449 / Coaching

4

Any tips on how to crack/practice numerical parts of case interviews? Any "standard" framework to apply?

4 answers

  • Upvotes
  • Date ascending
  • Date descending
Best Answer
Book a coaching with Francesco

100% Recommendation Rate

3,275 Meetings

11,963 Q&A Upvotes

USD 449 / Coaching

Hi Anonymous,

in terms of how to approach math in the case, this is what I would recommend:

  1. Repeat the question – candidates sometimes do mistakes answering the wrong question in the math part
  2. Present how you would like to proceed from a theoretical point of view (you may ask for time before presenting if you initially don't know how to approach the problem)
  3. Ask for time and perform the first computations
  4. Present the interviewer interim steps to keep him/her aligned – don’t just say the final number
  5. Continue with the computations until you find the final answer
  6. Propose next steps on the basis of the results you found

In terms of general math tips, this is what I would recommend:

  1. Use correctly 10^ powers in your math computation. For example 3.2B/723M can be transformed in 3200*10^6/732*10^6, which makes it easier to deal with math
  2. Ask if it is fine to approximate. When you have to deal with math in market sizing, and sometimes even in business cases, you are allowed to approximate math to simplify the computation. In the previous example, for instance, you could transform the computation in 320*10^7/73*10^7, making the overall computation faster.
  3. Keep good notes. One of the reasons people do mistakes with big numbers is that they don't keep their notes in order, thus forget/misreport numbers
  4. Divide complex math in smaller logical steps. This is something you can use for big numbers after the application of the 10^ power mentioned above. If you have to compute (96*39)*10^6, you can divide the first element in 96*40 - 96*1 = 100*40 - 4*40 - 96*1 = 4000 – 160 – 100 + 4 = 3744*10^6
  5. Use shortcuts for fractions. You can learn by heart fractions and thus speed up/simplify the computation - the most useful to know are 1/6, 1/7, 1/8, 1/9.

Finally, in terms of practice before the interview I would recommend to practice math under pressure - not just math. Many candidates are totally fine with calculating 67% of 67 in a quiet environment, but freeze if you ask this suddenly in a case interview.

To practice for this, try always to use a timer with a strict time constraint when you practice math – this will create pressure and help to replicate the actual environment of the interview.

Hope this helps,

Francesco

Hi Anonymous,

in terms of how to approach math in the case, this is what I would recommend:

  1. Repeat the question – candidates sometimes do mistakes answering the wrong question in the math part
  2. Present how you would like to proceed from a theoretical point of view (you may ask for time before presenting if you initially don't know how to approach the problem)
  3. Ask for time and perform the first computations
  4. Present the interviewer interim steps to keep him/her aligned – don’t just say the final number
  5. Continue with the computations until you find the final answer
  6. Propose next steps on the basis of the results you found

In terms of general math tips, this is what I would recommend:

  1. Use correctly 10^ powers in your math computation. For example 3.2B/723M can be transformed in 3200*10^6/732*10^6, which makes it easier to deal with math
  2. Ask if it is fine to approximate. When you have to deal with math in market sizing, and sometimes even in business cases, you are allowed to approximate math to simplify the computation. In the previous example, for instance, you could transform the computation in 320*10^7/73*10^7, making the overall computation faster.
  3. Keep good notes. One of the reasons people do mistakes with big numbers is that they don't keep their notes in order, thus forget/misreport numbers
  4. Divide complex math in smaller logical steps. This is something you can use for big numbers after the application of the 10^ power mentioned above. If you have to compute (96*39)*10^6, you can divide the first element in 96*40 - 96*1 = 100*40 - 4*40 - 96*1 = 4000 – 160 – 100 + 4 = 3744*10^6
  5. Use shortcuts for fractions. You can learn by heart fractions and thus speed up/simplify the computation - the most useful to know are 1/6, 1/7, 1/8, 1/9.

Finally, in terms of practice before the interview I would recommend to practice math under pressure - not just math. Many candidates are totally fine with calculating 67% of 67 in a quiet environment, but freeze if you ask this suddenly in a case interview.

To practice for this, try always to use a timer with a strict time constraint when you practice math – this will create pressure and help to replicate the actual environment of the interview.

Hope this helps,

Francesco

(edited)

Book a coaching with Udayan

98% Recommendation Rate

94 Meetings

2,730 Q&A Upvotes

USD 209 / Coaching

Numerical parts of the case study are not designed to be standalone. The objective is to get your level of comfort with the analytical elements of the case, test your problem solving abilities and to know that you can do some basic calculations (with one or two tricky elements to solve). There are a few ways to prep for this

1. Get quick at basic arithmetic - practice multiplications, divisions and squares etc. often. It will take a few hours of practice for your brain to get used to solving these much more quickly which frees up time to focus on problem structuring

2. Spend time upfront thinking about and structuring the problem. The math part of most cases is not the toughest part, the toughest part is truly understanding what the question is asking for and then structuring the solution accordingly

3. Practice different types of problems - some are straightforward estimations (e.g., calculate the number of customers required to break even), some require more time (e.g., how many cars pass through a given bridge at one time) and some are a hybrid. You can never predict what you will get but more practice will let you get comfortable that you can solve these problems.

If you give yourself the flexibility to approach each problem on its own merits vs following a structured framework you will be a lot better off. To do so its the usual answer of practice till you get comfortable with these problem types

Numerical parts of the case study are not designed to be standalone. The objective is to get your level of comfort with the analytical elements of the case, test your problem solving abilities and to know that you can do some basic calculations (with one or two tricky elements to solve). There are a few ways to prep for this

1. Get quick at basic arithmetic - practice multiplications, divisions and squares etc. often. It will take a few hours of practice for your brain to get used to solving these much more quickly which frees up time to focus on problem structuring

2. Spend time upfront thinking about and structuring the problem. The math part of most cases is not the toughest part, the toughest part is truly understanding what the question is asking for and then structuring the solution accordingly

3. Practice different types of problems - some are straightforward estimations (e.g., calculate the number of customers required to break even), some require more time (e.g., how many cars pass through a given bridge at one time) and some are a hybrid. You can never predict what you will get but more practice will let you get comfortable that you can solve these problems.

If you give yourself the flexibility to approach each problem on its own merits vs following a structured framework you will be a lot better off. To do so its the usual answer of practice till you get comfortable with these problem types

Book a coaching with Vlad

97% Recommendation Rate

404 Meetings

11,349 Q&A Upvotes

USD 239 / Coaching

Hi,

All good recommendations here. The key tip here - there is a limited number of types of math questions that you can get.

I believe the best way to practice is by taking ALL available casebooks (There are 30-40 casebooks that I know of) and going through ALL the math tasks in these cases. Pls skip the cases, just do the math.

Best!

Hi,

All good recommendations here. The key tip here - there is a limited number of types of math questions that you can get.

I believe the best way to practice is by taking ALL available casebooks (There are 30-40 casebooks that I know of) and going through ALL the math tasks in these cases. Pls skip the cases, just do the math.

Best!

Book a coaching with Robert

96% Recommendation Rate

317 Meetings

3,639 Q&A Upvotes

USD 219 / Coaching

Hi there,

Francesco's answer is an excellent summary of how to approach the numerical part - it's exactly how it should be done.

Just to make sure, I would like to add to point 5./6.:

  1. Be sure that you finally answer exactly your interviewer's question. From an interviewer's perspective it's extremely annoying to have candidates do the right stuff and then not giving the very precise answer I was asking for. E.g. when I ask about the % cost savings, I don't want to hear 5.000 USD per unit as an answer. And: C-level execs are usually much less patient in getting their questions precisely answered than your interviews, that's why interviewers look also on such small details like that.
  2. When it comes to next steps, especially McKinsey is very picky in terms of looking at the big picture (what does this answer mean in the general context of the case/problem we are trying to solve?) and the according "so what", as well as getting specific measures as next steps which are actionable (as usual, in a structured way, like short-term vs. long-term measures, .....).

Hope that helps as additional inputs!

Robert

Hi there,

Francesco's answer is an excellent summary of how to approach the numerical part - it's exactly how it should be done.

Just to make sure, I would like to add to point 5./6.:

  1. Be sure that you finally answer exactly your interviewer's question. From an interviewer's perspective it's extremely annoying to have candidates do the right stuff and then not giving the very precise answer I was asking for. E.g. when I ask about the % cost savings, I don't want to hear 5.000 USD per unit as an answer. And: C-level execs are usually much less patient in getting their questions precisely answered than your interviews, that's why interviewers look also on such small details like that.
  2. When it comes to next steps, especially McKinsey is very picky in terms of looking at the big picture (what does this answer mean in the general context of the case/problem we are trying to solve?) and the according "so what", as well as getting specific measures as next steps which are actionable (as usual, in a structured way, like short-term vs. long-term measures, .....).

Hope that helps as additional inputs!

Robert

Related BootCamp article(s)

Interviewer-Led vs Candidate-Led cases

Case Interviews can be led by the candidate or by the interviewer: In Candidate-led cases the main challenge is the structure. In Interviewer-led cases the main challenge is to adapt quickly

Related case(s)

McKinsey Questions

Solved 39.0k times
McKinsey Questions Tell me of a situation where you had an opinion and no one seemed to agree with you. What was your goal when you decided to join university / work / clubs / a sports team? Did you have a goal that you were not able to reach? What did you do? What do you want to be remembered for and how are you achieving it? What is your typical way of dealing with conflict?
4.5 5 862
| Rating: (4.5 / 5.0) |
Difficulty: Intermediate | Style: Fit Interview | Topics: Personal fit

Tell me of a situation where you had an opinion and no one seemed to agree with you. What was your goal when you decided to join university / work / clubs / a sports team? Did you have a goal that you were not able to reach? What did you do? What do you want to be remembered for and how are you ... Open whole case

MBB Final Round Case - Smart Education

Solved 15.3k times
MBB Final Round Case - Smart Education Our client is SmartBridge, a nonprofit educational institution offering face-to-face tutoring services. The client operates in the US. The mission of SmartBridge is to help as many students as possible to complete studies and prevent that they drop from the school system, in particular in disadvantaged areas. The client is considering starting operations for its services in the Chicago area. They hired us to understand if that makes sense. Due to the nonprofit regulation, SmartBridge should operate on its own in the market, without any partnership. How would you help our client?
4.6 5 529
| Rating: (4.6 / 5.0)

Our client is SmartBridge, a nonprofit educational institution offering face-to-face tutoring services. The client operates in the US. The mission of SmartBridge is to help as many students as possible to complete studies and prevent that they drop from the school system, in particular in disadvant ... Open whole case

Espresso, Whatelse?

Solved 9.0k times
Espresso, Whatelse? Espresso Whatelse is an Italian company that produces coffee and espresso machines since 1908. It is the Italian market leader and has a strong presence overall in Europe. In 2019, Espresso Whatelse has increased its revenues but it has seen declining profit margin. Your client wants to understand the root causes of this 2019 trend and how to increase its profit margin again.  
4.6 5 455
| Rating: (4.6 / 5.0)

Espresso Whatelse is an Italian company that produces coffee and espresso machines since 1908. It is the Italian market leader and has a strong presence overall in Europe. In 2019, Espresso Whatelse has increased its revenues but it has seen declining profit margin. Your client wants to understand ... Open whole case

Hot Wheels

Solved 4.8k times
Hot Wheels Problem definition: Our client is Korean Car Parts (KCP), a multi-national original equipment manufacturer (OEM) of car parts based in Korea. They've recently seen a decline in profits and have brought us in to understand how to address this falling profitability.
4.6 5 284
| Rating: (4.6 / 5.0)

Problem definition: Our client is Korean Car Parts (KCP), a multi-national original equipment manufacturer (OEM) of car parts based in Korea. They've recently seen a decline in profits and have brought us in to understand how to address this falling profitability. Open whole case

Motivational questions – FIT interview preparation

Solved 3.5k times
Motivational questions – FIT interview preparation During this exercise, we will deep-dive in 4 of the most common Motivational questions asked in FIT interviews:   Why Consulting? Why this particular company? (McKinsey, Bain, BCG, others) Why this particular location? *Particularly relevant to people re-locating or choosing an office not in their region Why this particular specialized business function *Only relevant when not applying for a general role (e.g., McKinsey Advanced Analytics, BCG Gamma, etc.) *box-open green* *See Graph 1 – Note: "Motivational" are one of the 4 types of questions you can find in FIT interviews. *box-close* ➥ Graphs from the Integrated FIT Guide for MBB
4.5 5 62
| Rating: (4.5 / 5.0)
Difficulty: Intermediate | Style: Fit Interview | Topics: Personal fit

During this exercise, we will deep-dive in 4 of the most common Motivational questions asked in FIT interviews: Why Consulting? Why this particular company? (McKinsey, Bain, BCG, others) Why this particular location? *Particularly relevant to people re-locating or choosing an office not ... Open whole case