It really depends on the role you are looking for. If working with data and doing analysis, you need some knowledge in stats and probability. If you are working on simulations, you will need basic calculus and algebra. If you are looking at game development, you will need basic trigonometry and vector arithmetic. The one thing you don’t need is mental arithmetic because you have a computer.

That being said, you can get by without these skills, it just becomes harder to see what you need to do, even if you would know how to implement it. This is alleviated if you are working in a team however.

Depends how much time you spend in a text editor. If it is just for a few config edits and stuff, honestly there is little reason to learn. The real benefit is if you spend a lot of time editing text due to the time saved using more powerful commands. There is the additional benefit that vi/vim is installed on practically any Linux box, so you will almost always have a familiar editor to hand in an unfamiliar environment.

Go through the tutorial. It is quite good and teaches things incrementally with real world examples. Just run vimtutor to start.

Client: “Can you switch these two colours, you have 1 minute to fix it or you’re fired!”

Result:

And even when they do control themselves consistently without fail, most people would still look down on them if they knew…