@fadedsparrow10 hours ago
Direction checks saved me from this exact mistake later in prep.
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@avocadoheron614October 9, 2026United States
I got the right case-math setup but used the wrong sign. How bad is that?
- Case Math
My formula was right, but I treated a cost reduction as negative and ended up with the opposite direction in the final number. I caught it when the interviewer questioned the result. How serious is that kind of error?
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How can I prepare for a Bain interview if my math skills are very weak?
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Mayank G.Coach
Mayank G.CoachPrioritize the math fundamentals that actually appear in cases, then practice explaining your setup clearly under time pressure.
If the interviewer gives me an assumption, should I still sanity-check it?
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Sometimes the interviewer gives me a number or assumption directly, like average price or customer volume. I usually just plug it in. Should I ever question or sanity-check numbers that come from the interviewer?
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Mayank G.CoachUse interviewer-provided information as given unless there is a clear inconsistency or you need clarification about what the number represents.
The interviewer stepped in and did part of the math after I made a mistake. How bad is that?
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Mayank G.CoachNot automatically. One arithmetic mistake does not by itself determine the entire interview.