Bài 1:
uses crt;
var n,kq,i:integer;
begin
write('Tong la: ',kq);
readln;
end.
Bài 2:
uses crt;
var n,kq,i:longint;
begin
clrscr;
kq:=kq*i;
write('Tong la: ',kq);
readln;
end.
Bài 3:
uses crt;
var kq,i:longint;
begin
write('Tong la so chan 1 den 20 la: ',kq);
readln;
end.
Bài 4:
uses crt;
var kq,i:longint;
begin
readln;
end.