Array help!

Hi
I have a noob question about arrays.
I have two arrays:
var array1 = new Array();
array1[0] = “1”;
array1[1] = “7”;

I know that these are in string format, but this is necessary for the whole code (i think!) but I want to be add these to values together, to get the value of 8, however if you do:
var answer = array1[0] + array1[1];
Then it just joins the 2 values to give 17, however if you times them, it treats it like a number.
Is it possible to add them to get the value of 8 in another way without having to remove the speech marks from the array value???
Thanks
Rhys