Applying a specific functions over a range of cells

Howdy,

I'm trying to extract specific numbers from a string of letters and numbers, using this formula:

'=VALUE(MID($B3,FIND("a",$B3,1)+1,(FIND("b",$B3,1)-1)-FIND("a",$B3,1)))'

which is basically trying to extract a number between an 'a' and a 'b' in the string of characters. However there are is a long list of these said character strings (from B3 to B54) and I was wondering if there was a way to edit my formula so that I am able to get the sum of the specific numbers from each of the cells.

I have already tried

'=SUM(VALUE(MID($B3:B54,FIND("a",$B3:B54,1)+1,(FIND("b",$B3:B54,1)-1)-FIND("a",$B3:B54,1)))'

and things like that, but I always get a '#VALUE!' error.

Please Help
Rikolos

=SUMPRODUCT(VALUE(MID($B3:B18,FIND("a",$B3:B18,1)+1,(FIND("b",$B3:B18,1)-1)-FIND("a",$B3:B18,1))))

for range b3- b18