I got through the interview process while being somewhat bad at mental math. I am a bit better at doing math with pen and paper.
Is being good at mental math valuable, important, or crucial when starting in consulting? I would assume that you do quite a lot of calculations when estimating numbers. When you do calculations: Would you usually have a pen and paper, excel/calculator, or do you often do the calculations purely mentally?
How often do you need to calculate without a calculator during your first years at MBB?