Help in Quantitative parts

Hello!
This is something that many candidates seek to strengthen! 

My suggestions:
1) Have a clear structure at the beginning of the case. This in itself is something that comes with practice but you can strengthen through seeing many types of cases, reviewing (and IDing the patterns), reviewing set frameworks etc. This will give some clarity to your direction and also indicate what type of information you need to keep an eye out for.
2) Note-taking: Be sure to have a good system so as not to overwhelm yourself but also to note information that you need. I recommend having 5 pages when casing (1 for each structure and recommendation and 3 for the body of the case -you can have extras for scrap calcs. things like that) 
Then create a system for yourself that when you have very important data you can ID it (if you need it later)(like maybe underline) and also for your answers (maybe red box) so that you're quick to see it when you need it.

Hope this helps!

 

Great question! 

Here’s the paradox:
It’s not your math that’s weak. It’s your thinking under noise.

When you solve alone, your brain runs in “quiet mode.”
When you solve live, you’re in “verbal mode” - half your mental bandwidth is spent listening, talking, managing eye contact, organizing the paper, and trying not to look lost.
That’s why even engineers and quants crumble in live math. The bottleneck isn’t calculation, it’s cognitive load management.

Let’s fix that systematically.

One thing to understand

In an MBB interview, quantitative excellence ≠ speed or accuracy.
It’s transparency of logic under pressure.
Your interviewer must be able to follow your brain in real time - not admire your final number.
That means:

• You don’t “calculate,” you narrate the path of calculation.
• You don’t “plug numbers,” you show the reasoning behind the equation before touching the numbers.
• You don’t “jump to result,” you walk through checkpoints that prove you’re in control.

One thing to try

Next time you practice, simulate the live environment properly:

1. Verbalize everything. Read the data aloud, paraphrase it, and write it down in a structured table before touching your calculator.
2. Anchor your math to the business logic. Don’t start with “revenue = price × quantity.” Start with “to assess profitability, I need revenue and cost - let’s start by building revenue.” Then go into the formula.
3. Use a fixed note layout.
   • Top left: key question
   • Top right: structure of the problem
   • Middle: data table (unit, volume, price, etc.)
   • Bottom: calculation steps
     Your notes become your cockpit. When you always fly the same cockpit, you stop crashing under turbulence.

One mental model

Think of quantitative analysis as storytelling with numbers.
Every step must make sense to a non-quantitative client.
That’s what MBB tests - not if you can multiply, but if you can teach a CFO why the number makes sense.

One small exercise

Pick any case prompt and do the math aloud while recording yourself.
Then re-watch.
Count how many times you:

• Jumped into formulas before defining variables
• Did silent calculations
• Gave a number without a sentence wrapping it (“This means…”)

Those are your weak links. Fix those, and your “quantitative problem” disappears.

At McKinsey, I advanced candidates who made me feel safe during math.
Safe that they’d never lose a client in the fog of numbers.
That’s your real goal - not impressing with brilliance, but earning trust through clarity.

This is one of the core skills for becoming a client-ready problem solver.
It’s not about getting better at math.
It’s about mastering how to think like a consultant when math gets loud.

Hope this helps!
Sidi

___________________

Dr. Sidi S. Koné

Hi! This is a common challenge but here are a few ways to navigate:

1) Just like the initial case prompt, make a note of all key information and play it back to the interviewer to ensure you have all key numbers noted correctly

2) You can take a moment to process the information before progressing. The goal for this moment will be for you to set up your main equation i.e. in order to solve the question at hand, listing an equation that tells you what variables you need 

3) Some of these variables might have been shared with you in the quant prompt, and some others you might need to ask for. Sometimes, there is no further information available, in which case you can make assumptions but only after agreeing with the interviewer that it is okay to do so

4) The goal for quant questions is casing is not just to get to the right answer but to communicate with clarity - state your equations, which variables you are working with, and what is missing clearly

5) Finally, state what the answer means for the main question you are solving for 

Even when you practice alone, it might help to approach it in the same way. You can record yourself and play it back to see where there is room to improve. Good luck! 

Yes. It would help, though, to see you doing a calculation live to tailor the recommendations. 

But, high level, it sounds like it might help to break down the calculations into steps

1. Start by playing back the numbers that you've heard and validating them. Make sure that you also understood the question correctly. 

2. Focus only on developing the approach / logic of solving the calculation question and do so on your own. Then discuss it and align it with the interviewer.

3. Only after that, get to the numbers. You can also perform the computations on your own and then take the interviewer through them. 

4. Interpret and contextualise the result. 

You might also find this resource helpful:

• Cheatsheet: The Must-Know Consulting Terms for Interviews

Feel free to reach out directly if you have any questions I can help answer.

Best,
Cristian

Best,
Cristian

Hi there,

This is a very common challenge, even for people with strong math backgrounds. The challenge usually isn’t the math itself, but processing info verbally under time pressure. A few tips:

• Repeat the question back out loud before calculating: helps buy time for you to think and it shows structure
• Structure your notes: make your own system of denoting variables for what you need to calculate (e.g. Mt = Market size today, M3 = Market size in 3 years, etc.)
• Use math tips for cases: use 10^x for large numbers; divide/multiply using shortcuts (e.g. when dividing by 40, divide by 10, then 2, then 2)

With a bit of structured note-taking and repetition, this gets much easier fast. 

Hey there, this is really common even for engineers. When numbers come “out loud,” it helps to first write everything down in a structured way, columns for variables, assumptions, and units. Then repeat key numbers back to the interviewer to make sure you understood correctly. Break calculations into small steps and think aloud as you go, so both you and the interviewer can follow your logic. Practicing with a friend who reads numbers to you can really train this skill. Also, develop shorthand symbols and consistent layouts for your notes to make scanning and calculating faster. best, Alessa :)