bash scripting problem

[Daniel Dalton]

Hi,

I am learning to shell script. One of my tasks is to print the value of 
two numbers been added together. But first that final value must be 
assigned to a variable.
So I write:
#!/bin/bash
#Print the value of 2 numbers added

x=10
y=15
z=$x+$y
echo $z
exit 0

I get 10 +15 as the output.

I want to get 25.
What am I doing wrong?
-- 
Daniel Dalton

http://members.iinet.net.au/~ddalton/
daniel.dalton47 at gmail.com