Crystal Report in C#

All you need to do is Formatting Numbers in Crystal Reports[^]

right click on the field, choose format object, then select the number tab.
then click on the customize button. then unchecked the thousands Separator : Symbol : ,
check box.

You are done.

if your field is string
Within Crystal, you can do it by creating a formula[Field Explorer-> Formula Field-> right click->new Formula-> give a name] that uses the ToNumber function. It might be a good idea to code for the possibility that the field might include non-numeric data - like so:

If NumericText ({field}) then ToNumber ({field}) else 0

now follow the above steps for the formula field.