9.524=9+.524
.524=524/1000, so 9+.524=9+(524/1000).
Reduce terms with obvious numbers first, like 4.
524 and 1000 are both divisible by 4. (524/4)/(1000/4)=131/250.
This is the lowest possible reduction because 131 is prime, therefore 131 and 250 share no common factors.
9.524=9+.524=9+(524/1000)=9+(131/250)= 9 131/250.
