Equal, or exist (3)
I believe the answer is:
are
I believe this clue is a double definition.
'equal' is the first definition.
(I've seen this in another clue)
'exist' is the second definition.
('they exist' means 'they are')
(Other definitions for are that I've seen before include "Unit of land measure equal to 100 square metres" , "(We/you/they) exist" , "live" , "Is, in the plural" , "(We/they/you) exist" .)