Hey,
>> Firstly, I am confused as to how the doubled values are being added to
>> the undoubled number in the above example. It looks like only the>> individual numbers of the doubled values are being added
The assignment states "Add the digits of the doubled values and the undoubled digits", so it specifically states to add digits (which are 0 1 2 3 ... 9) and that is why when you have [2, 3, 16, 6] you do not simply do 2 + 3 + 16 + 6 but you do it digit wise 2 + 3 + 1 + 6 + 6. That is [2, 3, 16, 6] becomes "23166" and you simply sum all the digits.
>> If we are to follow the algorithm described (double the value of "every
>> second digit" beginning from the right, last digit unchanged", then the
>> above numbers are identical EXCEPT For the last digits (1 and 2)
The assignment states "Add the digits of the doubled values and the undoubled digits", so the sum will be different for the two numbers provided in the example because both doubled and undoubled values (their digits actually) are being summed. That is why for the first number validates gives True and for the other it gives False.
Hope that was clear enough for you to understand. You got confused by a single sentence in the assignment.
Konstantin