23/

uses crt;
var n,s,k: longint;
begin
clrscr;
write ('Nhap N: '); readln (N);
s:=0;
while n<>0 do
begin
k:=n mod 10;
s:=s+k;
n:=n div 10;
end;
writeln ('Tong cac chu so: ',s);
readln;
end.

24/

uses crt;
var n,s,k: longint;
begin
clrscr;
write ('Nhap N: '); readln (N);
s:=1;
while n<>0 do
begin
k:=n mod 10;
if k mod 2=0 then s:=s*k;
n:=n div 10;
end;
writeln ('Tich cac chu so chan: ',s);
readln;
end.

25/

uses crt;
var n,d,k: longint;
begin
clrscr;
write ('Nhap N: '); readln (N);
d:=0;
while n<>0 do
begin
k:= n mod 10;
if k mod 2=1 then d:=d+1;
n:=n div 10;
end;
writeln ('Co ',d,' chu so le');
readln;
end.

23:

uses crt;
var n,i,t:integer;
begin
clrscr;
write('Nhap n:'); readln(n);
write('tong tat cac cac chu so cua ',n,' la:');
for i:=1 to n do
begin
 t:=t+n mod 10;
 n:=n div 10;
end;
write(t);
readln
end.

24:

uses crt;
var n,t:integer;
s:longint;
begin
clrscr;
write('Nhap n:'); readln(n);
write('tich tat cac cac chu so cua ',n,' la:');
s:=1;
while n<>0 do
begin
 t:=n mod 10;
 if t mod 2=0 then s:=s*t;
 n:=n div 10;
end;
write(s);
readln
end.

25:

uses crt;
var n,i,t,dem:integer;
begin
clrscr;
write('Nhap n:'); readln(n);
write('so  cac cac chu so le cua ',n,' la:');
dem:=0;
for i:=1 to n do
begin
 t:=0;
 t:=t+n mod 10;
 if t mod 2<>0 then dem:=dem+1;
 n:=n div 10;
end;
write(dem);
readln
end.