I can prolly do what I want simply by adding a resistor in series.
(3.3K +333 Ohms in series gives approx 3.6 K yes?)
However, lets assume for a moment that i've been locked in a tall tower by an evil tyrant dual combi boiler monster who will not release me until i've gotten as near as possible to 3.6K using the existing 3.3K and another resistor in parallel.
I had a look on google and it tells me (someone who once posted on usenet tells me) that in order to work out the resistance of two restors in parallel, you multiply the two values, then add the two values, then divide the output of the multiplication by the output of the addition.
However, how can you work it backwards, if you have the value of one resistor and the total resistance you are aiming at, but want to know what value to use for the other?