you did not add XL in the description

Thank you! This seems to solve the issue.

Your code will fail in VScode as well if you test it with the input that causes your code to break. In this case, your code fails on an input of "" (an empty string)

I also think that it's more a language issue than a problem with the description. But having said that, I wonder: is the note about counting multiples of 15 only once even needed? I think it's a part of the challenge, and it should become clear after analyzing the problem statement and examples?

Sorry, but that seems to be a problem on your part, not in the instructions. I've changed the for a, but I still don't see how you could read this:

i thought that only 15 should be added to the sum excluding all commom multiple of 3 and 5.

 If a number is a multiple of both 3 and 5, only count it once.

         ^---------------------------------------------^       

15 is a multiple of both 3 and 5, but you add it only once, the same for 30, 45 and so on.

Note: If the number is a multiple of both 3 and 5, only count it once.
this note is misleading. i thought that only 15 should be added to the sum excluding all commom multiple of 3 and 5.

Please state which language you're working in when raising issues.

Your Prolog solution is buggy, so I'm closing this īssue as it's not a problem with the kata itself.

To fix your solution, consider what would happen if I called solution(-1, R)

è avanzato qualcuno che inizia da zéro avrà molto dificulta

the tests keep failing even if it's the program is working even for 7 seven digits numbers

I agree it needs updating. Several questions directly on the translation.

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( Haskell )

example tests do not compile

Note: the user's attempted language is Golang