When flying, ATC gives the message " Cambrian approach roger, altitude 2980" Can anyone tell me what altitude 2980 means ???

Many thanks.

Are you sure that it's "Altitude"? I'd say it's actually "altimeter", and that would mean your altimeter setting should be 29.80 (inch Hg), in order to have your altitude displayed correctly.

Yes that makes sense, thankyou for the reply.