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Enhancing skills for mental math

Sarsen

Good evening, folks,

Could you please share your experience how did you improve your mental math skills?

Maybe there are some methods or tools that I might found useful, which I don't know yet?

Appreciate your experience in enhancing this skill?

Thanks, Sarsen

(edited)

Vlad replied on 04/09/2018
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School

Hi,

Here is how you can improve your math skills:

1) Mental math - train, train, and train again

  • Learn how to multiply double digit numbers (https://www.youtube.com/watch?v=6ndkkPZYJHo)
  • Learn the division table up to 1/11 (i.e. 5/6 = 83.3)
  • Learn how to work with zeros (Hint: 4000000 = 4*10ˆ6)
  • Use math tools (Mimir math for iOS), Math tool on Viktor Cheng website to practice

2) Critical Reasoning (for PST)

  • GMAT test CR and IR parts (Official guide and Manhattan prep)
  • Mckinsey practice tests
  • PST like tests from the web

3) Working with tables and graphs and deriving conclusions

  • Study "Say it with Charts" book
  • Check all available MBB presentations and publications. Practice to derive conclusions and check yourself with the actual ones from the article/presentation
  • GMAT IR part (Official guide and Manhattan prep)
  • Learn basic statistics (Any GMAT or MBA prep guides)

4) Case math

Practice common market sizing topics (Airport passenger flow, real estate volumes, subway passenger flows, car usage, etc.). You should become comfortable with making assumptions

Learn key financial topics (P&L and balance sheet and how to analyze them, Basic Valuation principles via NPV and comps) and case math:

  • Interest rates calculations
  • Compound margin
  • NPV using the Rule of 72, Perperuity
  • CAGR using the Rule of 72
  • Currencies exchange calculations
  • Speed, time, distance calculations
  • Equations, systems of equations
  • Ratio & Proportions
  • Solving the problems by calculating the area of the triangle
  • Profit / breakeven formula
  • Correlations, outliers (being able to spot on the graphs, tables)

Good luck with your interviews!

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