sum data column in crystal reports

See more:

.NET3.0

.NET

hi all,

please help me!

i developed windows project in c#.
in my project i use crystal report,i want to sum all the values to one of the column.i use sum() through rithclick the field name,but it display count of values,here my codings

my column name is A
data type is int32(also i use decimal,double)

i get sum() in the list,but it count the values in 'a'th column,what's wrong with my work.