1)

uses crt;

var i,n,s: integer;

begin

clrscr;

write ('nhap n: ');  readln (n);

s:=0;

for i:=1 to n do s:=s+i;

writeln ('tong la: ',s);

readln;

end.

2);

uses crt;

var i,n,s: integer;

begin

clrscr;

write ('nhap n: ');  readln (n);

s:=1;

for i:=1 to n do s:=s+i;

writeln ('tich la: ',s);

readln;

end.

3)

uses crt;

var i,n: integer;

begin

clrscr;

write ('nhap n: ');   readln (n);

write ('cac so chan nho hon hoac bang ',n,' la: ');

for i:=1 to n do

if n mod 2=0 then write (i:4);

readln;

end.

4)

uses crt;

var i,n: integer;

begin

clrscr;

write ('nhap n: ');   readln (n);

write ('cac so le nho hon hoac bang ',n,' la: ');

for i:=1 to n do

if n mod 2=1 then write (i:4);

readln;

end.

Câu 1 :

uses crt;

var i, n, S : integer;

begin

clrscr;

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

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

write('S = ', S);

readln

end.

Câu 2 :

uses crt;

var i, n, S : integer;

begin

clrscr;

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

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

write('S = ', S);

readln

end.

Câu 3 :

uses crt;

var i, n : integer;

begin

clrscr;

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

write('Cac so chan : ');

for i := 1 to n do

if i mod 2 = 0 then write(i,'  ');

readln

end.

Câu 4 :

uses crt;

var i, n, S : integer;

begin

clrscr;

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

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

if i mod 2 = 0 then S := S + i;

write('S = ', S);

readln

end.

Câu 5 :

uses crt;

var i, n, S : integer;

begin

clrscr;

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

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

if i mod 2 <> 0 then S := S + i;

write('S = ', S);

readln

end.