Numbers making a noise in examinations (8)
I believe the answer is:
ordinals
'numbers' is the definition.
(I know this)
'a noise in examinations' is the wordplay.
'a noise' becomes 'din' (din can mean a loud noise or disturbance).
'in' means one lot of letters goes inside another.
'examinations' becomes 'orals' (oral is a kind of examination).
'din' placed within 'orals' is 'ORDINALS'.
'making' acts as a link.
(Other definitions for ordinals that I've seen before include "Figures indicating position" , "Numbers" .)