It is quite easy to evaluate $\frac{a}{b}\bmod m$ when $a$, $b$ and $m$ are integers and $\gcd(b,m)=1$ by replacing $\frac{1}{b}$ with an inverse of $b$ modulo $m$.
But, is it possible to evaluate that when $\gcd(b,m)\neq1$? For example I tried to find $\frac{16}{7}\bmod 7$ following way:
We are actually to find some $x$ such that $\frac{16}{7}\equiv x \pmod 7$
As modular arithmetic permits multiplication$16\equiv 7x \pmod 7$
But, $7x\equiv0 \pmod 7$
Hence $16\equiv0 \pmod 7$ which is absolutely wrong.
What wrong am I doing or should I conclude no such $x$ exists?
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