Accuracy matters, but one small arithmetic error is not automatically fatal if your setup is sound and you recover cleanly.

The bigger goal is reliable, transparent calculation. The case-interview mental-math guide covers the core techniques for improving both accuracy and speed.

Write intermediate numbers, sanity-check the result, and correct yourself directly if you notice a mistake. Repeated errors or answers that you cannot explain are much more concerning than one corrected slip.

I made one math mistake in final round and still passed. I corrected it after checking the magnitude.

Accuracy first. Speed came naturally once I stopped panicking.