How to add values in a variable in Unix shell scripting?

Question

I have two variables called count1 and count7

count7=0
count7=$(($count7 + $count1))

This shows an error \"expression is not complete; more tok

Answer 1

the above script may not run in ksh. you have to use the 'let' opparand to assing the value and then echo it.

val1=4

val2=3

let val3=$val1+$val2

echo $val3