Sometimes you may need to sum a "non numeric" (or text) field. Crystal will not allow this to happen until we convert the text field to a numeric one.
Let's assume the text field we want to sum is called "Price".
Step #1 : Create a new formula field.
Step #2 : Within the new formula field, use the following : ToNumber(Price).
The "ToNumber" function in crystal will now allow us to Sum the formula field within the report.