I cant use radius or out of radius when i'm doing a command in the snapshot 17w50 example: /kill @e[r=10]

This was changed with the new command system. Now you can use @e[distance=..10]. For more details on these changes, see here:

https://www.reddit.com/user/Dinnerbone/comments/6l6e3d/a_completely_incomplete_super_early_preview_of/

Take care! 🙂

Wait how do I do minim and max distance