program tong_100_so_tu_nhien;
uses crt;
var i, S: integer;
begin
S := 0;
for i := 1 to 100 do
S := S + i;
writeln('Tong cua 100 so tu nhien dau tien la ', S);
readln;
end.
Var i,s:integer;
Begin
i:=1;
s:=0;
While i<=100 do
Begin
s:=s+i;
i:=i+1;
End;
Write('Tong la ',s);
Readln;
End.