I tried this solution and it failed all the random tests. I saw it here, went back and tried it again and it still failed?

For me it correctly returns "10". I think you copied something wrong maybe?

this code doesn t work correctly.

I copied it then tried to sum 1+1 and got 1011.

addBinary('2', 3);

It's not required for this Kata but it's good to know for external use when converting between denary and binary. See here for more information.

why need >>> 0

I learned a new method in Ruby!

Not sure why this was marked as "Clever".

straight from stackoverflow. nice.

I thought it was pretty readable...

I think it's pretty obvious that I wasn't concerned with the readability of this solution.

Clever use of ternary operator, but not exactly easy to read.

There was a bug in the initial solution...