adding two fields on LOAD

Hello,

This is a very simple question, but somehow I can´t find the answer...

I´m using Qlik Sense to visualize some data from a EXCEL file. There are several fields on the EXCEL file that show the amount of money owned for a particular length of time:

LOAD

    FechaCorte,

    lugar as OrigenFactura,

    tipo,

    rsocial1 as Vendedor,

    code as NIT,

    rsocial2 as Deudor,

    fecha,

    factura,

    dia30 as deuda30Dias,

    dia60 as deuda60Dias,

    dia90 as deuda90Dias,

    dia120 as deuda120Dias,

    dia150 as deuda150Dias,

    diamas as deudaMasde150Dias,

    dia30 + dia60 + dia90 + dia120 + dia150 + diamas as DeudaTotal

FROM [lib://Soportes Recaudos (vliberal_rdimarco)/CarteraTotal.XLS]

(biff, embedded labels, table is [Cartera Total VL+PG$]);

So, I want to create a new field that shows the sum of all of these fields. I called that field "DeudaTotal" (TotalOwned). I did it like this:

    dia30 + dia60 + dia90 + dia120 + dia150 + diamas as DeudaTotal

But somehow that new field is always Blank.

The other values load OK. Dia30 is the value of an invoice due for less than 30 days. Dia60 is between 30 and 60 days, and so forth.

Any help with the syntaxis of that sum is welcomed.

Thanks a lot!.