A quantity or total (6)
I believe the answer is:
amount
I believe this clue is a double definition.
'a quantity' is the first definition.
(I know that quantity can be written as amount)
'total' is the second definition.
(I know that total can be written as amount)
(Other definitions for amount that I've seen before include "Add up or be equivalent to" , "value" , "Size" , "Sum of money" , "Quantity, sum" .)