Passing Subreport Value to Main Report

In my Report I am passing the Total of Subreport to display in the Main Report for that I am using the below Formula,

In Subreport,

WhilePrintingRecords;
Shared Numbervar EvTotal:= cdbl({Evaluation_Details.NOOFCOPIESEVALUATED})

In Main Report,

Shared NumberVar EvTotal;
EvTotal;

but when I Include the Formula for displaying in the Main Report it is Dispalying "0" instead of Total of SubReport