Question

How many rational numbers are there strictly between $0$ and $1$ such that the denominator of the rational number is $80$?

Answer 1

We know that, $\frac{0}{80}=0$ and $\frac{80}{80}=1$

So, the numbers between $0$ and $1$ having denominator $80$ are $\frac{1}{80},\frac{2}{80},\frac{3}{80},\frac{4}{80},...\frac{78}{80},\frac{79}{80}$
Therefore, there are $79$ such positive rational numbers.