- Sử dụng for ... do :

uses crt;

var i, n : integer; S : real;

begin

clrscr;

write('Nhap so n = '); readln(n);

S := 1; for i := 0 to n do

S := S * 1 / ((i + 2) * (i + 3));

write('S = ', S : 2 : 5);

readln

end.

- Sử dụng Whie .. do :

uses crt;

var i, n : integer; S : real;

begin

clrscr;

write('Nhap so n = '); readln(n);

S := 1; i := 0;

while i <= n do begin

S := S * 1 / ((i + 2) * (i + 3));

i := i + 1; end;

write('S = ', S : 2 : 5);

readln

end.

- Sử dụng for ... do :

uses crt;

var i, n : integer; S : real;

begin

clrscr;

write('Nhap so n = '); readln(n);

S := 1; for i := 0 to n do

S := S * 1 / ((i + 2) * (i + 3));

write('S = ', S : 2 : 5);

readln

end.

- Sử dụng Whie .. do :

uses crt;

var i, n : integer; S : real;

begin

clrscr;

write('Nhap so n = '); readln(n);

S := 1; i := 0;

while i <= n do begin

S := S * 1 / ((i + 2) * (i + 3));

i := i + 1; end;

write('S = ', S : 2 : 5);

readln

end.