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fast math

## Best resources for math improvement? (for a complete number novice!)

fast math math mental math Quantitative skills
Neueste Antwort am 16. Nov 2020
<p>Whilst the preparation for case studies is going okay, I hit huge hurdles when I hit numbers.</p> <p>I am looking for resources that will help me start from the very basics when it comes to mental math.</p> <p>I have come across Victor Cheng's course https://www.caseinterview.com/mental-math (though his 'ultimate' option is way out of my budget!) and FastMath course. Does anybody have any reviews or recommendations on courses to take to improve mental math, please?</p> <p>https://www.caseinterview.com/mental-math</p> <p>Thank you in advance!</p>
Hi, Basically, you need to develop 3 calculation skills: 1) Learn how to multiply double-digit numbers (https://www.youtube.com/watch?v=6ndkkPZYJHo). 2) Learn how to work with zeros. Best way - always use 10^power ... (ganze Antwort lesen)
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## Moltiplications/divisions with 6+ digits numbers, estimation math_Tricks

Case Maths estimation fast math GMAT MathSkills IB Guessestimation Math problem
Neueste Antwort am 16. Nov 2020
<p>Is there any way/trick to solve estimation math? I was reading the comments here that apply to 4 digits numbers, how about millions and billions?</p>
Hi Anonymous, in general, the main issues with big numbers is forgetting zeros during operations. Potential tips to deal with big numbers are the following: Use correctly 10^ powers in your math computation. For e ... (ganze Antwort lesen)
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## Feeling stuck at Case Practice

case math case math' Case Maths case structure Case structure and frameworks Case Structuring Consutingmath fast math GMAT MathSkills IB Structure
Neueste Antwort am 26. Okt 2020
<p>Hello everyone! :)</p> <p>I started my case interview preparation two months ago. First I started reading Case on Point and Victor Cheng book and LOMS. Then I did the free course on craftingcases.com which I find to be the most helpful resource online. Finally, I started practicing cases, I have done around 35+ cases and I identified two biggest weakenesses:</p> <p>1. Structuring: Develop insightful and MECE frameworks.</p> <p>2. Problem solving: By this I mean during the math part know how to solve the problem after they give you some data for this.</p> <p>To tackle each of them I started by structuring, to that I bought Crafting Cases Structuring Drills course, which was very helpful, however I still feel my frameworks are still weak. I still need to focus on the problem solving part.</p> <p>Today when I did again a live case interview I found myself struggling again, somehow this is quite discouraging specially when you compare with people who have had the same amount of practice as you and solving a case for them seem to be very natural while I find myself struggling.</p> <p>I would like to know two things: </p> <p>First: How can I improve my problem solving skills during the math part? Maybe doing some GMAT Problems? Does anyone has any good advice for this?</p> <p>Second: How can I stop being stuck during my preparation and become more natural?</p> <p>Thank you very much. </p>
Hi there, Two tips : 1. Practice, practice, and just dont give up. Give yourself time & celebrate little successes. Take a break for couple of days here and there and do something fun/creative to unclock the tra ... (ganze Antwort lesen)
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## Mental Math Help!

Case Timing fast math mental math Mental Maths
Neueste Antwort am 24. Sep 2020
<p>Hi everyone, </p> <p>I just came off a practice case with an MBB senior manager - their biggest feedback for me is that I need to do my math "faster" (I took around 45 mins to do a 30 min case because I spent too long talking my thoughts out loud). Not sure about anyone else, but when I increase my speed I also increase the errors I make, and often descend into an anxious mess after I've messed up. Does anyone have concrete suggestions for how to improve this? I know can perform the maths well when not under pressure, but I don't want to get penalized for taking it slow. </p> <p>Anyway, I'll obviously continue to practice, but would love some suggestions on the most efficient way to do this as my "real" interview is in 10 days!</p>
When I was a candidate myself, I made a stupid math mistake (double counting) for my final round interview with a senior partner. Fortunately, it didn't lead to a rejection but I was asked to come back for an additional ... (ganze Antwort lesen)
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## Mental math app for practising fractions/percentages

case math fast math fraction math mental math percentage
Neueste Antwort am 8. Aug 2020
<p>Hey guys, </p> <p>If you want to practice mental math fractions and percentages for your case interviews, I've released an app called 'Case Math' on the iOS store to do just that. https://apps.apple.com/us/app/case-math/id1507653375?mt=8&amp;ign-mpt=uo%3D4 </p> <p>I've designed it to focus only on fractions for three key reasons:</p> <p>1) Fractions are involved in many calcs: market sizing, margins, market share etc. </p> <p>2) Fractions are typically harder and less practiced than other operations - addition, subtraction &amp; multiplication</p> <p>3) I couldn't find other mental math apps that allowed practice using non-exact answers. E.g. in a case you'd typically be allowed to estimate 6/17 to within 5-10% </p> <p>I've found it helpful to incorporate into my daily drills and thought others might as well. If you give this app a try, I'd love to hear your thoughts on it - if you think it's useful, and what other features you think would help improve it.</p> <p>Thanks,</p> <p>Richard</p>
Hello Richard, Thanks for sharing! Actually I have many candidates that struggle with mental math, I will take a look to your app. Best, Luca
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## Math for case interviews

Case Interview fast math math
Neueste Antwort am 31. Jul 2020
<p>I was just curious to know what kinds of math and algebra one should know for case interviews? The online web practice sites that randomize numbers are useful for helping you improve multiplication, addition, division, and so forth, but I am wondering what you might need to know beyond those basic. Everyone says that all you need for interviews is "back of the envelope" math, but I find that a bit misleading, as I've done fairly complicated practice problems on McK PST practice tests.</p> <p>In other words, what kinds of math, besides the back of the envelope stuff, should one know and practice when preparing for case interviews?</p> <p>Thanks.</p>
Hi, I recommend downloading all casebooks available online and check the math problems. You'll have a good list. Here are some of them to keep in mind: Interest rates calculations Compound margin NPV using the ... (ganze Antwort lesen)
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## Mental Math ressources

case math fast math math logic
Neueste Antwort am 22. Jul 2020
Anonym gab die beste Antwort am 22. Jul 2020
<p>Hello, </p> <p>Do you have any reliable (free online or book) resources to develop mental math techniques? I need a methodology and a way to progress.<br> <br> Thanks in advance !<br> </p>
Hi A, Here is math app for practicing math fractions and percentages from one of PL participant https://apps.apple.com/us/app/case-math/id1507653375?mt=8&ign-mpt=uo%3D4 Also, here is a tool provided by PrepLoung ... (ganze Antwort lesen)
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## Is quick mental math a skill that can be learned?

fast math
Neueste Antwort am 16. Jul 2020
<p>I want to be true to myself. I think I have what it takes to be a consultant, but my problem is math. I am not quick and when somebody stairs at me while asking a math question is like if all my insecurity comes out and just blocks me. I panic and can't do the easiest multiplication (let alone the divisions).</p> <p>I have two months ahead: do you genuinely think I can make it? Can I learn how to be quick at math? </p>
Hi Anonymous, it seems your problem is not the math itself, but the math under pressure. This is a very common problem for many candidates. The majority of the people are actually fine with math when there is no pre ... (ganze Antwort lesen)
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## Division techniques

case math Division fast math Math problem math test mental math
Neueste Antwort am 8. Jul 2020
<p>Hi, I have final round at all 3 MBBs coming up in the next two weeks and would like to make sure I'm as prepared as I can be.</p> <p>I'm fairly confident in my quant skills, but <strong>my only real insecurity remaining is <u>divisions</u></strong>. I'm just not good at it: I don't know a lot of shortcuts and for those divisions where no shortcuts apply, I have a really hard time doing the math.</p> <p>For instance: 6,300,000 divided by 7,200. I just have absolutely no idea how to tackle this. My best try is to attempt long division, meaning the long and painful process of telling myself:</p> <p>(1) Basically figure out how much is 630/72 and then add the zero's.</p> <p>(2) Ok 72 doesn't fit 10 times in 630, how about 9? No neither, ok it fits 8 times.</p> <p>(3) Ok how much is 72*8? It's 576, so 630-576 = 54.</p> <p>(4) Ok let me make this 540 and see how much 72 fits into this, and I'll divide by 10 later.</p> <p>(5) etc ...</p> <p>Any advice at all please? How would you calculate 6,300,000 divided by 7,200, or any other large division of the kind?</p> <p>A sincere thank you in advance!</p>
Hi, There are two techniques that you can use: 1) Learn how to work with zeros. Best way - always use 10^power instead of zeros Example: 300x9000 = 3*10ˆ2 x 9*10ˆ3=3x9*10ˆ(2+3)=27*10ˆ5 Handwritten it looks no ... (ganze Antwort lesen)
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## Math: word problems exercises

Case Interview case interview preparation case math fast math math Math problem mental math Word problems
Neueste Antwort am 21. Okt 2019
<p>Hey all, Do you know of a link where you can practice math 'word problems'? I have noticed that during my case prep that sometimes I have a difficult time deriving equations from information given in cases.</p> <p>Any info on the subject e.g. book/site is also appreciated. Many thanks.</p>
Hi, Something that helped my candidates - download ALL casebooks available online and go through the math problems in the cases. They will give a good sense of required business terminology. Then you can google what y ... (ganze Antwort lesen)
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## Request for a division table for percentage conversions

case math Division fast math Math tool
Letzte Aktivität am 8. Dez 2018
<p>Hello everyone! Realised that division seems to be the hardest to grasp among the +-x/, and most often than not divisions are required to convert fractions into percentages ie. 5 in 6 people converts to 83.3% ie. the end product can't be rounded to a whole. Is there anyone who can provide an extensive conversion table or the link to one which encapsulates such weird fraction-percentage conversions? Thanks!</p> Hey there, I made the following quickly on Excel. However, I wouldn't advise you to try memorise the whole thing, as it's a) a lot to try remember and b) doesn't have that much value. Rather, memorise the first column ... (ganze Antwort lesen)
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## Math tricks for small decimal numbers

fast math Math problem
Letzte Aktivität am 9. Nov 2018
Anonym A gab die beste Antwort am 7. Sep 2017
<p>Hello together,</p> <p>I'm wondering if anybody might have a nice trick for me to deal with divisions with small numbers. For example I'm struggeling with cases like this : 0.024 / 0.8 = ?</p> <p>Of course I can directly see that it must be something with 3 and if I do the long way of expanding the 0.024 to a bigger number I come to the right conclusion of 0.03. However, it simply takes me too much time. For multiplications with large numbers I do the trick with x 10^n and with that I'm really fast.</p> <p>Maybe someone knows a nice way to 1.) avoid mistakes with the zeros after the comma and 2.) to speed up the calculation.</p> <p>Thanks a lot in advance!</p> <p>Regards,</p> <p>Jana</p>
Hi Jana, It won't work where you have really ugly numbers but one trick to keep in mind is the 'invert and multiply'. So to use your case: 0.024/0.08 = (0.024/1) / (4/5) = 0.024 * 5 / 4 ... (ganze Antwort lesen)
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## How to quickly calculate and analyze market share tables?

Exercise fast math Logic Math
Letzte Aktivität am 25. Sep 2018
Anonym gab die beste Antwort am 25. Sep 2018
<p>Dear all,</p> <p>I stumbled upon this table in a case and I did figure out that prices for company BYB must be higher, but I think I took too long in calculating by how much the prices differ. Before I already realized that 40K buses are sold in the US and the market size in USD can be 6 billion USD. <br> <br> However, calculating now for each the market in usd and units and then getting the price for each company does not only seem to take too much time, I also assume that interviewers expect a short cut here. I know that the short cut would be dividing the market share in usd percentage by the market share in units percentage for each company and then figuring out whats the percentage difference in price - BUT why is this so? Mathematically I can derive it, however, I still tend to take too much time.</p> <p>Very happy to get some feedback on how to calculate such a table quickly using short cuts (and fast math) and also I would like to know (when dealing with market sizes tables) when I have to calculate the absolute numbers in order to compare it and when can I just compare percentages. </p> <p>Thanks a lot! </p> <p><img alt="Calculate Market Share Table" src="/uploads/qa/questions/2517/images/Screen%20Shot%202018-09-25%20at%2002.36.15.png"></p>
Not sure whether I get the question... So BYB has 38% \$-marketshare and 34%-unit share, then their \$-share is overindexed by (38/34 = 1.12 (approx.)). So if every bus costs 150k (6 bln / 40 k), then their busses cost ... (ganze Antwort lesen)
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## Compound Annual Growth Rate McKinsey PST Questions

CAGR fast math Math tool McKinsey McKinsey PST
Frage bearbeitet am 28. Jan 2018
<p>Hi,</p> <p>How would you approach those two excersises below? I am preparing alone (without a tutor and math/ GMAT prep. background) so I found those tasks rather difficult for me.. </p> <p>I've found suggestion here: https://www.preplounge.com/en/consulting-forum/math-prep-cagr-without-excel-any-tips-750#a1460 to use Taylor series - but that approach seems not to be applicable for all the cases (i.e. if the (1+x)^a=V is (1+(-x))^a - decreasing by 1 p.p. is not helpful at all)..</p> <p>I am looking for several generic&amp;fast approaches to cover all possible cases (i.e. solutions are too close to each other, growth rate is negative, etc.)</p> <p>1. The Revenue in Y0 = 11.64. We project annual growth to be 7%. Which of the foll. is the closest estimate of the projected Revenue in Y5?</p> <ul> <li>a) 15.2</li> <li>b) 16.3</li> <li>c) 17.4</li> <li>d) 18.5</li> </ul> <p>My approach:</p> <p>1) 11.64(1+0.07)^5 = y</p> <p>then either:</p> <p>2) use binomial formula: (1+x)^5 = 1+5x+10x^2+10x^3+5x^4+x^5 =&gt; x = 1.403</p> <p>or </p> <p>3) (1+0.07)^5 = 1.07^4 * 1.07 = 1.15*1.15*1.07=1.323*1.07 = 1.42</p> <p>4) y = 11.64*1.4 = 16.3 =&gt; <strong>b)</strong></p> <p>2. Number of cows 3 years ago - 2 150 000, now - 500 000. Assuming cows declining at a constant rate, which of the foll. is the closest estimate of the annual % drop in the number?</p> <ul> <li>a) 20%</li> <li>b) 25%</li> <li>c) 40%</li> <li>d) 55%</li> </ul> <p>My approach:</p> <p>1) 2 150 000 (1-x)^3 = 500 000</p> <p>(1-x)^3 = 0.232</p> <p>2) x=20%:</p> <p>0.8^3 = 0.64*0.8 = 0.512 =&gt; wrong</p> <p>3) x=25%: too close to 20% =&gt; wrong</p> <p>4) x=40%:</p> <p>0.6^3 = 0.36*0.6 = 0.216 ~ 0.232</p> <p>5) x = 55%:</p> <p>0.45^3 = 0.20*0.45 = 0.09 =&gt; wrong.</p> <p>6) <strong>c)</strong></p> <p>Thank you in advance!</p>
Hi, whenever you are required to solve a compound interest problem you can go with two different logic: 1. When you want to know how much will value X will be in Y years given Z% growth each year: 1.1. Logic: You ... (ganze Antwort lesen)
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