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Help! - How can I improve my math skills?

Math problem mental math quantitative
New answer on Jan 22, 2023
6 Answers
713 Views
Anonymous A asked on Jan 19, 2023

Hi Community!

I got invited so a couple of interviews in February and already practice business cases for a while now.

Nevertheless I still have big issues with my mental math and quantitative skills.

I am just not a heavy math person…

When somebody is asking me to calculate something on the fly/spot I feel super overwhelmed and have felt a blockade.

My written math skills are ok but I have difficulties with mental math and basically feel not confident and secure in the quantitative field.

How can I improve my skills?

I already use the mental math tool on preplounge but it not really tagging my issues.

Do you have any recommendations?

Maybe prep materials, tools, software or a course / workshop I can book?

Thanks so much in advance!

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Best answer
Francesco
Expert
Content Creator
replied on Jan 20, 2023
#1 Coach for Sessions (4.000+) | 1.500+ 5-Star Reviews | Proven Success (➡ InterviewOffers.com) | Ex BCG | 10Y+ Coaching

Hi there,

Q: My written math skills are ok but I have difficulties with mental math and basically feel not confident and secure in the quantitative field. How can I improve my skills?

It is difficult to answer without a concrete example of what exactly you find challenging (ie, you might be fine with multiplications but not with divisions). 

Please also note that most of the time you won't need to perform mental math and will be able to write down the numbers. 

I reported some general tips below.

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

  1. Repeat the question – sometimes candidates do mistakes answering the wrong question
  2. Ask for time and present how you would like to proceed from a theoretical point of view
  3. Perform the math and present the interim steps to keep the interviewer aligned – don’t just say the final number
  4. Continue with the math until you find the final answer
  5. Propose next steps on the basis of the results you found

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In terms of general math tips and avoiding mistakes, I would recommend the following:

  1. Use correctly power of 10. For example, 3.2B / 723M can be written as 3200*10^6 / 732*10^6
  2. Ask if it is fine to approximate. You can ask the interviewer if you can approximate complex math. If allowed, this will help to solve simpler problems. In the previous example, you could get 320*10^7 / 70*10^7
  3. Keep good notes. This helps to avoid to forget/misreport numbers
  4. Divide complex math into multiple simpler steps. For example: (96*39)*10^6 → 96*40 - 96*1 = 100*40 - 4*40 - 96*1 = 4000 – 160 – 100 + 4 → 3744*10^6
  5. Learn the main fractions results. You can learn by heart fractions and speed up/simplify the computation - the most useful to know are 1/6 ~ 17%, 1/7 ~ 14%, 1/8 = 12.5%, 1/9 ~ 11%.

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I would also recommend to practice math under pressure - not just math. Many candidates are totally fine doing 67% of 67 in normal conditions, but freeze if asked this suddenly in a case interview.

In order to do so, try always to use a timer with a time constraint when you practice math – this will create pressure and help to replicate the actual conditions of the interview.

Hope this helps,

Francesco

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Hagen
Expert
Content Creator
replied on Jan 20, 2023
#1 Bain coach | >95% success rate | interviewer for 8+ years | mentor and coach for 7+ years

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:

  • It's great that you have recognized your difficulty with mental math and quantitative skills and that you are taking steps to improve them. However, it's important to note that not being a "math person" might be an issue for you in the long run in strategy consulting, as quantitative skills are a fundamental aspect of the job.
  • Also, it seems to be more of a mental issue when you feel overwhelmed and have felt a blockade, which is common among people who struggle with math. It's possible that your mental block is more related to a high stress state than to math itself.
  • Here are some recommendations that may help:
    • Practice, practice, practice: The more you practice mental math and quantitative problems, the more comfortable you will become with them. Try using mental math and quantitative problem sets or flashcards to practice on a regular basis.
    • Take a math course: Consider taking a math course or workshop to refresh your knowledge and skills. This can help you build a solid foundation in math and make it easier to tackle more advanced quantitative problems.
    • Utilize online resources: There are many online resources available that can help you improve your mental math and quantitative skills. Websites like Khan Academy and Coursera offer math courses and tutorials that can help you review key concepts and practice problem-solving.
    • Use mental math apps: There are many mental math apps available that can help you improve your speed and accuracy. Some popular apps include ConsMath and  Mental Math Pro.
    • Try meditation: As mentioned, meditation and mindfulness can help you to reduce stress and increase focus and concentration, which can then help you to improve your mental math.
    • Seek help from a tutor: If you find that you are still struggling, consider working with a tutor who specializes in math and quantitative skills. They can provide personalized feedback and support to help you improve.
    • Consider addressing the mental issues: If you find that your mental block is more related to a high stress state or an emotional issue, seek help from a professional counselor or therapist who can help you to address those issues and provide you with the necessary tools to overcome them.

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

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Nicolas
Expert
replied on Jan 19, 2023
40% off 1st coaching Promo | #1 MBB Coach Canada & MENA | 8y+ Coaching & recruiting | BCG + Senior Exec | INSEAD MBA

Hello! 

First of all don't worry! It is completely normal as we are not used to doing since school as we have calculators / phones / excels … ! 

Maths in cases are never going to be complicated so it is important to understand the Type of maths that you will be required to do and focus your practice on that : percentages, divisions, multiplications, etc. 

In a case there are no penalties for writing down your maths and solving it manually - the important thing is to get the RIGHT answer! Sure speed might get you a few extra points, but ALWAYS better to be right than fast!

Good luck in your prep!! Let me know if you have other questions!
Cheers
Nicolas

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Alessandro
Expert
replied on Jan 19, 2023
Currently Morgan Stanley M&A | Former Oliver Wyman | MBA at London Business School | PIPE expert

Good morning!

Well first let us start saying that it will not be your mental math performance that will drive whether you get an offer or not. So do not feel overwhelmed!

The key for mental math is what is to improve your instant recognition skills. This means for example you should know instantly the whole 1-10 multiplication table, but also the basic percentage table (for example, 1/6 = 16.7% etc.), and know how how to move across different orders of magnitude (e.g., billions / millions = ?).

You should practice with that until you know the answer without thinking about it. 

After that, you should get trained to simplify the problem. For example: what is 19% of 590M? 

- 20% of 590 M is 118M. Ask yourself if that is enough to answer the question.

- If it is not, then deduct 1% which is 5.9 M.. 

- 118 M - 5.9 M = 112.1 M

There are many other tactics to simplify the problem, but hopefully you get the idea.

Good luck

Alessandro

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Anonymous B replied on Jan 19, 2023

Hey. We are in the same boat. I downloaded the app…mental math games on Google Play Store. It eases you in when it comes to mental math. You start with small numbers and you can focus on issues such as speed and the quality of math. I do it when I am bored or when I am travelling and before I go to sleep. It keeps building you up until you can solve more complex mental math problems. So I do that in conjunction with math drills to boost my confidence. It has been helping. You won't get better instantly but it helps.

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Ian
Expert
Content Creator
replied on Jan 22, 2023
#1 BCG coach | MBB | Tier 2 | Digital, Tech, Platinion | 100% personal success rate (8/8) | 95% candidate success rate

Regarding Improving Fast Math Skills

  • Math sheets (print these and do them on paper): https://www.math-drills.com/
  • Leverage the free preplounge resource:https://www.preplounge.com/en/mental-math.php
  • Rocketblocks is great for math in the context of a case

Some key formulas/concepts:

  • Breakeven
  • NPV (with + without growth, perpituity + 1-2 years from now)
  • % Change
  • ROI
  • Margin
  • Markup
  • Inventory turnover

Regarding Improving Axienty

1) Practice, practice, practice - just like playing an instrument, practice until it becomes second nature...then when you perform in front of an audience, muscle memory takes over from stage fright!

2) Practice with people who make you nervous - Don't keep casing yourself or casing with other PrepLoungers! You need to feel as nervous when practicing as you will in the real thing. To do so, you can do any (or all) of the following:

  • Ask for a buddy/case partner from target firms to which you're applying
  • Ask anyone you have a relationship with at your target firms to give you a practice case
  • Ask your school's career office to give you a case
  • Ask a coach to give you a case (and ask them to be tough/strict/non-friendly)
  • Still ask PrepLoungers to case you, but ask them to jump straight into it without conversation beforehand (i.e. simulate the real thing)
  • Change your enviroment - instead of casing at home, go to a library or office room. Changing the scenery may trigger you to be less relaxed

3) Practice with the unknown - ask people to give you "weird" cases. Ask people to throw everything they have at you (curveballs, confusing statements, etc.)...you'll get comfortable with tripping up (and recovering)

4) Practice fast math - You said you get nervous here...well, practice it until it's the easiest thing you've ever done! How? Use the following:

How to structure math in a case

  1. Have a seperate "math" scrap sheet of paper
  2. Grab a new sheet of paper every time you're entering a new phase of the case...number and title it
  3. Use tables to organize numbers
  4. Write out the equation before doing the math
  5. Never forget to write down units
  6. Circle key numbers AND write down the "so what"

Mental Math Q&A: https://www.preplounge.com/en/consulting-forum/is-quick-mental-math-a-skill-that-can-be-learned-5210

https://www.preplounge.com/en/consulting-forum/mental-math-help-7962

Interview Anxiety: https://www.preplounge.com/en/consulting-forum/tips-on-interview-anxiety-7095

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