Cho mình câu trả lời hay nhất nhé:
uses crt;
var n,m,s,d:longint;
begin
clrscr;
repeat write('Nhap so nguyen duong: ');readln(n);
until n>0;
d:=0; s:=0; m:=n;
repeat
d:=d+1;
s:=s+(m mod 10);
m:=m div 10;
until m=0;
writeln(n,' co ',d,' chu so');
writeln('Tong cac chu so cua ',n,' la ',s);
readln;
end.