Hi,
a few hints
At first you'd read the manual
www.limesurvey.org/manual/ExpressionScript_-_Presentation
And you may use all "implemented functions".
Examples:
In a question of type "equation" you enter the formula. Than the result is stored in this question, The same as in each other question.
sum of codes of two single punch questions: {sum(Q1.NAOK,Q2.NAOK)}
sum of assessment values of two single punch questions: {sum(Q1.valueNAOK,Q2.valueNAOK)}
sum of all subquestions in a "multiple numerical" question: {sum(that.Q1.NAOK)}
number of checked items in a multi question: {count(that.Q1)}
But best, you import the sample surveys about ExpressionScript and study them.
www.limesurvey.org/manual/ExpressionScript_sample_surveys
Maybe at first:
Relevance, Tailoring and Equations
Joffm