function res = convertGradeV1( score )
if score >= 90 
   res = 'A';
elseif score >= 80 & score <= 89 %! An error!
   res = 'B';
elseif score >= 70 & score <= 79
   res = 'C';
elseif score >= 60 & score <= 69
   res = 'D';
else
   res = 'Fail';
end   
   