I really cant understand whats wrong with this:

File looks like this:
55 11

Code:
cost=30
a= cut -c9-12 File
let a=${a}+${cost}
echo $a

The answer echo should echo 11+30(cost) however the output looks like this:
11
30

And also is there anyway to grep $2 without awk? or maybe awk grep $2?
wouldnt mind get this loop to work instead
for i in cut -c1-12 awk ' $2 ~ "^[0-9]" && $2 > 0 {$2='$i'} ' 5 `

Are you trying to sum second field from file with value in cost?

It does work if the f2 is actually on field 2 but its is on field 23 so to speak.
File do look like this:
Col10 51 Col23 11


Col10=10 space Col 23=23spaces

Thank you for the help mate.

Got it to work like this:
cost=30
a=$(( cost + $( cut -c23-26 5) ))
echo $a

If you have only two fields separated by spaces, then use awk