I guess the answer to your question is "Because you don't need to"

Overloading refers to two quite distinct situations. One is where you
want to involve parameters of different classes. You might want to add
two numbers or a number and a string. Ruby doesn't have anything like
the problem with that compared to more typed languages. The Ruby term is
"Duck Typing" which means Ruby will let you supply miscellaneous objects
and then see if they work in the context.

The second meaning - the one you demonstrated - is different numbers of
parameters. As other have pointed out, you can supply different numbers
of parameters to the same methods as long as you tell Ruby this might
happen and tell it how to deal with all the possibilties - with certain
constraints.

The problem is your example is pretty meaningless. You would be unlikely
to want to write a different method for each sum length.

Think of a more realistic scenario and then see if Ruby doesn't deal
with it.

(In the meantime, notice you really don't need to wrap your code in the
class Summer. I don't think it adds anything.)

(Oh dear, I shouldn't have said that...)

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