Can Cantor's diagonal number solve the issue of infinite lists?

[FactChecker]

One can use the decimal representation of the real numbers that everyone is familiar with since 4th grade and avoid the 999... issue simply by never allowing the infinite 9 representation in the list and never using 9 on the diagonal. That is concrete and familiar and does not require any abstraction to infinite lists. IMO, abstraction to the general list is easier to motivate after seeing a concrete example.

 

[TeethWhitener]

Do you disagree with any of this?

Nope. You win.

 

[Mark44]

One can use the decimal representation of the real numbers that everyone is familiar with since 4th grade and avoid the 999... issue simply by never allowing the infinite 9 representation in the list and never using 9 on the diagonal. That is concrete and familiar and does not require any abstraction to infinite lists. IMO, abstraction to the general list is easier to motivate after seeing a concrete example.

Sounds eminently reasonable to me.