I have missed out the ";" sign on first three statement.
So the error was coming.
local Numbervar a:={DataTable2.FieldDouble2}*1200/{DataTable2.FieldDouble2};
local Numbervar intpart:=CDbl(truncate(a));
local Numbervar decpart:=CDbl(a-intpart);
if decpart>=0.0 And decpart<=0.24 then
(intpart;)
else if decpart>0.24 And decpart<=0.74 then
(intpart+0.5;)
else if decpart>0.74 And decpart<=0.99 then
(intpart+1;)
else
(intpart;)