Small point but you would see "07" (pronounced ZERO-SEVEN) not "7"
At Sydney the crossing runway, used to be called the east-west is 07-25, so if you take/off land from the brighton end you are on 07 (ie facing roughly east at 070 degrees).
The two parallel runways are 16R-34L (main runway - so when landing to the south towards botany bay you are facing 160 degrees on the right hand runway) and 16L-34R (third runway).
Around the airport you will see these marked by white on red signs - mandatory guidance signs - placed at the edge of the runway - you will also see white pyrimad blocks called gable markers which mark the true edge of the runways...the so-called runway strip which extends beyond the tarmac and into the grass edge verges.
Because the numbers are for two ends of the same straight line they have a difference of 18 (ie. 180 degrees)...
The taxiways have just letters as markings (eg A for ALPHA, is the main taxiway for runway 16R-34L at Sydney running from by the International terminal all the way out on the Botany Bay spur) and are marked by yellow/balck signs - side-branches off taxiways get a number - so you will see B1 and B2 on signs as you go in and out of the main aporn area at QF in Sydney Domestic