[NumLock]

Код:

var
  i: Integer;
  v: Integer;
  r: Integer;
begin
  Randomize;
  Memo1.Clear;
  Memo2.Clear;
  for i:=1 to 20 do
    Memo1.Lines.Add(IntToStr(Random(9999)));
  for i:=0 to Memo1.Lines.Count-1 do
  begin
    v:=StrToInt(Memo1.Lines[i]);
    case v of
      0..999: r:=0;
      1000..1999: r:=1;
      2000..2999: r:=2;
      3000..3999: r:=3;
      4000..4999: r:=4;
      5000..5999: r:=5;
      6000..6999: r:=6;
      7000..7999: r:=7;
      8000..8999: r:=8;
      9000..9999: r:=9;
    end;
    Memo2.Lines.Add(IntToStr(r));
  end;
end;