What do you mean by 10 cases? you have 10 different tables or you have a variable named 'case'?

if ur table looks as case, x1 -- x25 then all you need to do is in the data step

data new; set data old; x=x1+...+x25;

please tell me hows your data looks like...

best regards,

In my statement, the 10 cases mean the sample size is the 10.

Yes, your right. it can be done in the data step as you said. But I don't think it is smart way.It also can be done using the function of sum.

It is difficult to deal with it as your method. Becasue there are 25 variables. If there are more than 300 variables. It is more difficlut. I want to use a loop  to deal with it based on macro language.