summation eliminating some elements

GAMS
1

i have a set i =1,2,3,4,5,6 and a variable x(i). how to ∑ x(i) eliminating 1 and 5?

2

Hi

set i /1,2,3,4,5,6/ ;

parameter x(i), mysum;
* assign some values
x(i) =ord(i);
mysum = sum(i$(i.val ne 1 and i.val ne 5), x(i));

display mysum;

Hope this helps
Renger

3

THANK YOU SO MUCH