ar i,n: integer;

s:longint;

begin

write('nhap so n=');readln(n);</strong></p><p><strong>s:=0;</strong></p><p><strong>i:=1;</strong></p><p><strong>while i<=n do</strong></p><p><strong>begin</strong></p><p><strong>s:=s+i; i:=i+1;</strong></p><p><strong>end;</strong></p><p><strong>write('tong cua',n,' so tu nhien dau tien la',s);

readln

end.
bài 2
 

Program bai_2;

Uses crt;

var

A,i,n:integer;

S:=0;

begin

writeln('moi nhap n: '); readln(n);

for i:=1 to n-2 do

begin

S:=S+1/(i*(i+2));

end;

write(S); readln;

end.
lát mét thầy
nhớ like cho t :))))