Sod that.
Assume that there are good visual landmarks nearby (which I think is a reasonable assumption, since otherwise how would you know how far off track you are). You're 2nm right of track, that's not really a huge amount in the grand scheme of things. You're 20nm from your destination - also not very far in the grand scheme of things, certainly not far enough to get lost.
Fly in the direction you'd originally planned, and look out of the left window until you see something you recognise. If the first thing you see is your destination airfield, that's fine - the ATZ will be at least 2nm radius, so you'll be perfectly placed for an overhead join.
There is a place for maths in flying - and unless the maths is very simple, or you've got two pilots on board, that place is on the ground. It's certainly not when you're approaching an airfield, with the extra workload of descending, getting set up for landing, looking for other arriving and departing aircraft which will most likely be at a similar altitude, and looking for the airfield itself.
FFF
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