Câu trả lời:

program tinh;

uses crt;

var a;b:integer;

   C:real;

begin

  clrscr;

write('ban hay nhap so nguyen a,a='); read(a);

write('ban hay nhap so nguyen b,b='); read(b);

C=a*b/2;

write('gia tri bieu thuc C la,C=',C);

delay(5000);

end.