fornula to convert text into number

[Rob]

Assuming that the text ALWAYS is a number followed by a
minus sign or a number with no other characters, this will
do the trick:
=VALUE(IF(RIGHT(A1,1)="-",MID(A1,1,LEN(A1)-1)*-1,A1))
There will be many more ways to skin this cat, this is one
way...