How to determine if the expansion of $1/n$ would be a recurring decimal expansion or not? for example, $1/7 = 0.\overline{142857}$ but $1/8=0.125$.
So, how to find if $1/n$ would be a recurring decimal expansion or not?
Note: Here, $1/6=0.16666\ldots$ is not a recurring decimal expansion.
It will be recurring as long as the denominator (in lowest terms) does not have a factor $2$ or $5$. There will be one non-recurring digit corresponding to the highest power of $2$ or $5$ in the denominator. So $6$ has one factor two and $1/6$ has one non-recurring digit. $8$ has three factors of two and $1/8$ has three non-recurring digits. $17$ has no factors of $2$ or $5$ and $1/17$ has no non-recurring digits.