Are all numbers divisible by 9 also divisible by 3?
Yes.
If integer n is exactly divisible by 9 then it can be expressed as n = 9*m where m is another integer.
This means that n/3 = 9*m/3 → 3*m, an integer.
.
The short answer is yes
Take any number, say 36
Work out the prime facrtors of 36
9*4=39
3*3*2*2=36
any number that you can get bu multiplying any of thes prime factors together will also be a factor of 36..
so
2
3
2*2
2*3
2*2*3
3*3
3*2*2
3*3*2
3*3*2*2