Shell Programming and Scripting

Hello My friends,

This is my new Thread and i am so newbie about Bash/shell code.

My first exam question is : there is a file (name is also File) and this file has 2 letters and 1 number. And number is in the middle. like this
a
2
c
I have to show only number on screen. And i did like this :

Code:

cat file | tail -n1 | head -n2

and i can see on my screen "2"

the next question is (it continues) : I have to SUM this number with shell code

and i created new kate file and name is total and wrote there :

Code:

c = cat file | tail -n1 | head -n2 

echo $total `expr $c + $c`

but i get "expr :syntax error" ?

How can i sum this number ?

thanks for your helps. Hope so i could explain myself.

Welcome!
Unless you can explain this is not in reference with a class, this thread is closed, you are to post here:
https://www.unix.com/homework-and-coursework-questions/

So I ask you kindly to repost there...

the requirements are not options...