You are answering your own question - since calculator is allowed, you don't necessarily have to spend as much time prepping for actual fast computations. However, you still should dedicate time to quickly setting up equations.

Additionally, if you will also be applying to McKinsey, the PST is non-calculator - so you may still want to practice this - although if your BCG test is coming up very soon, you could de-prioritise.

Hope this helps!

I was also allowed to use calculator during the test. I didn't touch it much tho. The test was logic-heavy, there isn't much calculation.

Dear A!

I actually agree with other answers.

But still: for practicing and improving your mental math you can find some apps and tools, besides Victor Cheng’s math tool (Magoosh's mental maths app, Mental math cards challenge app, etc).

Consulting math is very different than academic math. Working consultants - and consulting interview candidates - are always under time pressure. Results are what matter and answers are required simply to be good enough to guide business decisions, rather than being absolutely correct.

The time pressure in case interviews is severe and you cannot afford to waste time. But to make your calculations right you shouldn’t be in a rush. So, I would recommend you here to work on both - practice with time limitations and learn how to keep your mind peaceful and concentrated (it might be not so popular advice here, but mediations really make their job).

If you need any further help or career advice, feel free to reach me out.

Best,

André

(edited)