Calculation with positive and negative integers does not work and "NaN" appearing

[Kal_Lam]

Welcome to the community, @Sze! Use the coalesce as outlined in post discussed previously to solve your issue:

Using the if statement in Kobo

@velbon, you could do it as outlined in the image shared below: In the survey tab of your xlsform: [Image 1] In the choices tab of your xlsform: [Image 2] Data entry screen as seen in Enketo: [Image 3] Reference xlsform: If-Statement.xlsx (13.3 KB)