program phuongt; uses crt; var a, b, c, d, max: real; begin clrscr; write('Nhap a = '); readln(a); write('Nhap b = '); readln(b); write('Nhap c = '); readln(c); write('Nhap d = '); readln(d); max:=a; if max<b then max:=b; if max<c then max:=c; if max<d then max:=d; write('Gia tri lon nhat: ', max); readln end.
