At which level should I start a challenge?

Answer 1

When ever you ready.
its ok to lose, you still can learn

Answer 2

at any point you feel you got the basics down, and a calculator ready

just know, its very common to lose

Answer 3

thank you

Answer 4

You can start challenging at any level.
Here challenge doesn't mean competition,
Here challenge makes you learn more.

Answer 5

At any point when you feel comfortable but don't put calculator beside you..Lol...it won't sharpen your brain.

Answer 6

If u haven't started yet, start now. Challenge is much faster way to learn while keeping your interest level high... initially you will loose often but that's the only way of learning anything effectively, isn't it...?