Wrongly claimed to indicate a maths symbol (7,5)
I believe the answer is:
decimal point
'a maths symbol' is the definition.
(I know that decimal point is a mathematical symbol)
'wrongly claimed to indicate' is the wordplay.
'wrongly' indicates an anagram (I've seen this in other clues).
'to indicate' becomes 'point' ('point' can be a synonym of 'indicate').
'claimed' anagrammed gives 'decimal'.
'decimal'+'point'='DECIMAL POINT'
(Other definitions for decimal point that I've seen before include "It separates pounds from pence" , "What is in the middle of 1.5 and 2.5, say" , "Dot between figures" , "Dot in a number" , "I'm dot in place (anag)" .)