Hi @mazhar,
So if this is what you require, you could do it as outlined in the image below:
In the survey tab of your xlsform:
In the settings tab of your xlsform:

Data entry screen as seen in Enketo: (Wrong Entry)
Data entry screen as seen in Enketo: (Correct Entry)
Reference xlsform:
Calculation in a Matrix Question.xlsx (11.5 KB)
Have a great day!



