0
$\begingroup$

This question already has an answer here:

My question is very simple, if just as we say $5! = 120, 4! = 24,$ how can we say that $0! = 1$? Why did the ancient mathematicians conventionally consider $0!$ to be $1$? Then there's coming lot of anomaly, because $1! = 0!$. It's really strange. Can anyone state the exact cause?

$\endgroup$

marked as duplicate by user223391, Steven Stadnicki, Daniel Fischer Aug 16 '15 at 8:56

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ Who told you that ancient mathematicians used factorial? $\endgroup$ – Wojowu Aug 16 '15 at 8:47
  • $\begingroup$ So what did they used? $\endgroup$ – Aneek Aug 16 '15 at 8:48
  • 2
    $\begingroup$ As we know $n!=n\times (n-1)!$, Put n=1, you will get that $0!=1$ $\endgroup$ – Chiranjeev_Kumar Aug 16 '15 at 8:51
  • 1
    $\begingroup$ What "thing"? Also, what time period do you consider "ancient"? There was a time when 0 didn't even exist as a mathematical concept. $\endgroup$ – wltrup Aug 16 '15 at 8:52
  • 1
    $\begingroup$ Just do it on paper,, @Aneek $\endgroup$ – Chiranjeev_Kumar Aug 16 '15 at 8:54