I was entering the custom weekend through a cell reference: =DIATRABALHOTOTAL.INTL(B3;C3;A3;Feriados!$A$1:$A$54). So, at the cell A3 I put 1111011 without quote marks and thhen I got a #NÚM, inside the quote marks I got a #VALUE!. But using the apostrophe it worked, that's how I solved: '1111011. Inside the formula the correct way is use the quote marks like Jonmo1 said. Thanks everybody for all.