serial Dilutions

[Ndnassu]

Hi,

I am some what of a novel microbiologist (1st year ) who is having difficulty
with serial dilutions.  In particular, how does one know to use 9.9ml or 9.0ml
(diluent) or the .1ml or 1ml (inoculum) to reach desired dilution.  I am aware
that the total should = 10ml, but I am having difficulty manipulating the
amounts for the desired dilutions.  I know, it is most likely very simple, but
I am just not seeing it

Thanks in advance,
Yo