User blog comment:Nedherman1/About incomputables numbers/@comment-31966679-20180701191608

An uncomputable number is not well-defined because you could always do 1 + 1 + 1 + ... + 1 with the supposedly "uncomputable number" 1s to get the uncomputable number in a computable way.

For example, BB(1) = 1, but you can do 0 + 1 to get 1 and addition is computable.