UCAS offer- vaguely confused

I've just got my first offer; a conditional from Exeter.

I applied in a slightly unusual way, having just graduated from school. My current a-level grades are A* (Maths), A (Physics), and B (Philosophy and Ethics), along with a myriad of American qualifications of varying degrees of uselessness.
This year I intend to retake the offending A level, and do a self-taught further maths a level (predicted A*).

I applied to study Maths and Philosophy (through the flexible combined honors option), which had average entry requirements as A*AA-AAB.

I was under the impression that grades already achieved were excluded from an offer (e.g. unconditional or conditional: A), but mine appeared as AAA to include maths. Is this meant to happen?

It's probably because you're taking further maths. Some of your Maths and Further Maths modules are interchangeable, so they're just ensuring that you don't switch a really good Maths module for a not so good Further Maths on - for example bringing your Maths grade down to a B but giving you an A in Further Maths.

Thanks, I guess that could explain the maths, but wouldn't they at least remove the A in Physics if that was the case?

Does seem a bit odd - perhaps it's just that they give out the same offer to everyone and since there's a chance you might resit a few modules they've left it as conditional (even though you've already got an A!).
Double check that they aren't asking for AAA THIS YEAR - i.e. they will accept your already achieved grades. Some unis are a bit odd and won't count them... (The maths would have been included if this is the case because of the Further Maths complication I mentioned earlier).
Or maybe they just didn't notice that you had already achieved those grades...

I wouldn't have expected them to put A*AA-AAB if they made the same offer to everyone (most universities just have a single grade as their average/minimum offer- except for possible access arrangements), though it is possible. I haven't heard of universities asking for grades over one academic year except for those applying for Medicine/some Oxbridge courses (I would have expected a straight rejection if that was the reason).

Should I email them about it?

If you are at all confused about the conditions of your offer, it would probably be best to email the university for clarification.

However, you seem a little confused as to how unconditional offers work. You can't have an unconditional offer for one subject. The whole offer is unconditional, which means you don't have to do anything further in order to secure a place. As you are retaking a subject and taking a new one, they want you to achieve AAA (including maths). Therefore, they have given you a conditional offer. However, you are in a slightly unusual position of already having achieved some of the conditions of this offer.

Basically, they are asking you to get your philosophy grade up to an A, or achieve at least an A in further maths in order to secure a place.

Sorry, I didn't notice your reply. I wasn't confused about that so much (poor wording perhaps). I meant that I was hoping that as my grades were within the boundaries and my A* was in maths, that they may have made me an unconditional offer, and if that wasn't the case, I assumed they would make me an offer excluding the grades I'd already achieved. I emailed a particularly pleasant maths professor who clarified it for me- exactly what you said. I had thought this was the most likely scenario, but just wanted to make sure.