Skip to content 
The value of the exercise rests in the practice of careful reading. The numbers themselves remain straightforward once the language receives proper attention.
The riddle begins with a man. The nine sons follow. The sister completes the children. The addition produces eleven.
The same sequence supports repeated verification. Counting the sons produces nine. Counting the shared sister produces one. Counting the father produces one. The sum remains eleven.
The construction of the sentence creates the opportunity for the common error. The resolution rests in the recognition that one sister satisfies the condition for each of the nine sons.
Daily life presents parallel situations. Statements that appear to multiply can describe shared elements. Verification through careful attention produces the accurate picture.
The online discussions surrounding the riddle display a range of initial totals. The eventual arrival at eleven appears consistently among those who continue examining the words.