Lời giải:

uses crt;

var ln,a,b,c,d:integer;

begin

clrscr;

write('a='); readln(a);

write('b='); readln(b);

write('c='); readln(c);

write('d='); readln(d);

ln:=a;

if ln

if ln

if ln

writeln('so lon nhat trong 4 so la: ',ln);

readln;

end.