I collected the age of a respondent from date of birth(int((today() - ${dob}) div 365.25)).
I want to display the number 1 if the age of the person is less than one year. By default, It displays 0 if the person is younger than one year old.

Welcome to the community, @tba! Have you tried using the if-statement? Maybe this should override the 0 value and replace the same with 1 when the condition satisfies. It should be as follows:

if(expression, then, else)