Bài 1:

uses crt;
var n,i,t:integer;
begin
clrscr;
write('n='); readln(n);<br />t:=0;<br />i:=1;<br />while i<=n do<br />begin<br />t:=t+i;<br />i:=i+1;<br />end;<br />writeln('tong cac so nguyen tu 1 toi ',n,' la: ',t);
readln;
end.