Program neunhumotcaunoicothekhienemvui;
uses crt;
Var i,n,S,T : longint;
begin
clrscr;
write('nhap n:');readln(n);
S:=0;
for i:=1 to n do
S:=S+i;
write('tong n so tu nhien dau tien:',S);
T:=1;
for i:=1 to n do
T:=T*i;
write('tich n so tu nhien dau tien:',T);
readln;
end.

* Tính Tổng:

Program Tinh_tong;

uses crt;

var i,N : Integer;

      T:longint;

Begin

clrscr;

write('Nhap N:'); readln(N);

T:=0;

for i:=1 to N do T:=T+i;

writeln('Tong cua N so tu nhien dau la:',T);

readln;

end.

* Tính tích:

Program Tinh_tich;

uses crt;

var i,N : Integer;

      Tich:longint;

Begin

clrscr;

write('Nhap N:'); readln(N);

Tich:=1;

for i:=1 to N do Tich:=Tich*i;

writeln('Tong cua N so tu nhien dau la:',Tich);

readln;

end.