Hi,
[url]
www.limesurvey.org/manual/ExpressionScri..._Presentation#Syntax
[/url]
You use a nested IF-stament.
So both questions are shown to the participants?
You do not want just to calculate the age brackets hidden?
Then you insert a (hidden) question of type "equation" between both questions
{Q2=if(Q1 lt 20,1,if(Q1 lt 30,2,if(Q1 lt 40,3,if(Q1 lt 50,4,if(Q1 lt 60,5,6)))))}