Calculation in odk xls form

I hv made the odk xls questioner in that one right question carries 4 mark and negative question carries negative 1 (-1) marks done successfully....but any one of question not attempt carry 0 mark this is not i understood how to calculate.....please help me regarding these issue how to slove.

You probably need to turn your 'not attempt' responses explicitly into 0. See

can you give some example xls form...because I have an error org.javarosa.xpath.parser.ast.ASTNodeAbstractExpr@5c0369c4 in expression if( ${que1} =2,4(if( ${que1} ="",0,-1)))

Please help me regarding above issue


if(${que1}=2, 4, if(${que1}='', 0, -1))

thank you so much sir................