What do you do when you're in a challenge?

Question

If you're in a challenge, do you find it easy to do your challenge without the assist of a computer in front of you?
For a long time, I do my challenge with anyone off-hand, just trying to calculate myself. This is because I started with HTML. But how that I'm focused on python, it another ball game.
So do you use your computer to code during a challenge or you do it off-hand?

Answer 1

Yeah, it takes time if it's related to mathematics things.
Somehow, practice makes it perfect.
Do you know that the most of the challengers don't read the questions but they get 5 out 5.
It's like so

Answer 2

I cover the answers with my hand. I read the question/code.
I think about which knowledge/trick they want me to use.
I come up with what I think is the answer, then see if it is one of the multiple choice answers.