The number of a runway is that runway's heading, in tens of degrees.
In other words; if ATC directs you to Rwy. 5; the strip they want you to land at runs at 50 degrees - more or less. The other way to tell is that on larger airports - that is; all but the really small ones - the runway will have its number painted near the end. So the same Rwy 5 will have a big white '05' painted just above the end.
Now for the trick: How to get lined up on the right runway when you don't know the airport?
It's easy but it takes practice; it's called flying the circuit.
First; as you approach the airport tune into it's ATIS if it has one - that'll give you information on the weather and which runway is active. If it doesn't have ATIS; you'll have to skip this step - I advise practicing at an airport which has it until you get decent at doing circuits.
OK; ATIS tells you (right near the end of the message) which runway is being used - we'll stick with rwy. 5 for our example. That gives you time to get ready.
Lat's say you're approaching the airport on a heading of 310 degrees - exactly at right angles to the runway you'll be landing at.
When you approach the airport; call the tower and they'll direct you to the active - rwy. 5. When they do; turn
away from the heading so you're flying in exactly the opposite direction from rwy 5 - in this case; fly at 240deg. - the '5' will appear at the very bottom of the compass card (or direction indicator). Look at the airport; you'll see the runway you want; you'll be flying parallel to it. This is called the Downwind Leg of the circuit.
Now; keep flying straight until the airport's a couple of miles behind you. Turn 90 deg. toward the field; and fly until the runway is almost directly off to the side - 90 degrees, IOW. This is the Base Leg.
Now that you're off the end of the runway; turn until you're lined up with it; flying directly towards the end - you're now on Final; and can land.
(Seen from above; the Downwind, Base and Final legs form a big square 'U' shape - three sides of a rectangle.)
Sorry; I blathered - entering a circuit can be a bit confusing when you're just starting out; it gets easy pretty quickly. In FS2004; the easiest way to practice is to take the flying lessons built into the game - the instructor will lead you through all the steps.
Hope this helps!
