How to convert negative values from php to positive

I wanted to import the data in Excel 97 which contains a field called DetailAmount. All numbers are in positive. It should happened in the runtime that when the user enter negative value and when i store into variable(type Double) then I should convert to positive value. Could anyone PLease give me some tips.

Create a singleton Administrator object with a method public boolean isAdministrator(). If you in your MainFrame class want to refer an object then that objects scope must cover the method(s) where you want to reference the object. This you may also achieve by using the IF methos as follows:

If NegativeValue < 0 then
NegativeValue = NegativeValue * -1
End If

All you need is an object with a reference to both frames or both tables. If you add another parameter then the method signature (its name and its parameter types and sequence) is not the ActionListener interface implementation. Any objects interested in the login status of the Adminstrator register themself at that object and change their state accordingly when they receive an event.

I've tried inserting your expression into a query grid, but it's not working. In the constructor of this class, I created a new user by User user = new User(). I also tried to insert a minus sign (-) at the far left of the number I need to change to a negative, but it doesn't work either.