Numerical Reasoning for Consulting Firms
Consulting firms assess numerical reasoning in online tests and case interviews. They want to see that you can handle data, structure problems, and think quantitatively under pressure. Here's what to expect and how to prepare.
Where Numerical Reasoning Appears
Online tests – Many firms (McKinsey, BCG, Bain, others) use numerical reasoning tests early in the process. Format similar to SHL or similar providers: tables, charts, multiple-choice questions. Timed.
Case interviews – Numerical cases: profitability, market sizing, breakeven, growth. You work through the problem out loud. The interviewer may give you data or ask you to estimate.
Market sizing – "How many X are there in Y?" Classic consulting question. Tests structure, estimation, and comfort with numbers.
Profitability cases – "Company X is losing money. Why?" Revenue, cost structure, volume, price. You build a framework and work through the numbers.
Key Skills
Data interpretation – Read tables and charts quickly. Extract the right numbers. Spot trends and anomalies.
Structuring – Break problems into parts. Revenue = Price × Volume. Profit = Revenue − Costs. Market size = Population × Penetration × Frequency × Price.
Mental math – Percentages, multiplication, division. Round numbers. 15% of 280 = 42. 400 × 25 = 10,000.
Estimation – Order of magnitude. "Is it 100, 1000, or 10000?" Use round numbers. Show your assumptions.
Thinking out loud – Explain your reasoning. "First I'd calculate revenue. Then I'd look at costs..."
Preparation
- Practise numerical reasoning tests – Timed, with tables and charts. Get used to the format.
- Practise market sizing – Break down problems. Use round numbers. Practise out loud.
- Practise profitability frameworks – Revenue, costs, volume, price. Build the habit.
- Practise mental math – Percentages, multiplication. Quick and accurate.
Practice with numerical reasoning questions and the numerical reasoning test.
Frequently Asked Questions
Do I need to be perfect at mental math?
You need to be reasonably fast and accurate. Round numbers are fine for estimation. For exact calculations, show your work. Small errors are acceptable if you catch them or correct when prompted. Getting stuck in silence is worse than a minor error.
How do consulting numerical tests compare to SHL?
Many consulting firms use SHL or similar providers. The format is comparable: data sets, multiple-choice questions, timed. Practising SHL-style tests is good preparation.
What if I'm given a calculator in a case interview?
Use it for complex calculations. Don't rely on it for simple ones—mental math is faster and shows confidence. For market sizing, you often don't need a calculator if you use round numbers.