Thank you for this explanation, jeez, katas with ambigous explanations are terrible.

In first case - minimum list size always should be 3 numbers. You pass 2 numbers.
In second case - You last value in array is wrong. Step should be 3. You will get right answer change 19 to 17.

It doesn't seem to work in mine:
print(Practice9().find_missing(l: [2,14]))// 6 gives 8 instead of 6
print(Practice9().find_missing(l: [2,8,11, 14, 19])) // 5 gives 9 instead of 5

This is fundamental mathematics.

Neat solution!

could you please explain how exactly this works? What math rules did you use here?

WoW!!!

Thanks for this explanation.

It has random tests now, but it didn't make it any better...

Yet another bit of incomprehensible gibberish written by g964.

Is there a codewars for the english language?

"Eschew obfuscation, espouse elucidation" is ironic, not a template for how to talk to people.

Probably a little bit too late for me. I figured it out by deduction by looking at the unit tests, and reading other previous comments. Link makes a whole lot more sense. If the description would have said something like shift, I personally never heard rotate but now I know. Thanks.

Would you like a link to wikipedia in the instructions? I'm not the kata author tho, you'll have to ask him/her.

It might be ok but is a terrible way to explain it. Who comes up with these crypto explanations?

461 is not divisible exactly by 2, so(explanation is really messed up, I don't know what left means in the original description, maybe meant the other left):
Send first digit to the back:
73304 => 33047

When you rotate left, the first digit passes to the end. That part is ok.

There are tons of katas with really confusing explanations. I believe someone explained to me that if someone changes the description, all people that submitted, will be re-ran against the server posible overloading the server. I think this needs fixing, just don't automatically check all previous submissions. Alert user if they'd like to resubmit due to kata changes or something along those lines. This is a very easy problem to fix, that no one has had the strength to fix.

@seger Why in hell is your explanation hidden as a spoiler? That should be in the description!
Making a description cryptic shouldn't be the endgoal here.