Câu 2:

uses crt;
var A:array[1..100] of integer;
    N,i,s,dem:integer;
begin
   clrscr;
   s:=0; dem:=0;
   write('Nhap N: '); readln(N);
   for i:=1 to N do
   begin
      write('Nhap phan tu thu ',i,': ');
      readln(A[i]);
      s:=s+A[i];
      if (A[i] mod 3 = 0) then inc(dem);
   end;
   for i:=1 to n do writeln(A[i]);
   write('Tong la: ',s);
   writeln;
   write('Co ',dem,' so chia het cho 3');
   readln
end.

Câu 3:

uses crt;
var s:string[50];
    i,dem:byte;
begin
   clrscr;
   write('Nhap s: '); readln(s);
   for i:=1 to length(s) do
   if ('A'<=s[i]) and ('Z'>=s[i]) then inc(dem);
   if dem=0 then write('Khong có ki tu nao là chu in hoa co trong xau');
   write('So ky tu in hoa la: ',dem);
   readln
end.