diff --git "a/Excercise/\353\252\250\353\223\21004/Exercise2/Unit_ch4_2.pas" "b/Excercise/\353\252\250\353\223\21004/Exercise2/Unit_ch4_2.pas"
index ef99d72..51f3e38 100644
--- "a/Excercise/\353\252\250\353\223\21004/Exercise2/Unit_ch4_2.pas"
+++ "b/Excercise/\353\252\250\353\223\21004/Exercise2/Unit_ch4_2.pas"
@@ -28,14 +28,16 @@ implementation
 {$R *.dfm}
 
 procedure TForm1.Button1Click(Sender: TObject);
+const
+v: int64 = 6350000;
 var
   r:real;
+  a:int64;
 begin
-  r := SQRT(SQR(6350000 + StrToint(Edit1.Text)) - SQR(6350000));
+  a := SQR(v + StrToInt64(Edit1.Text));
+  r := SQRT(a - SQR(v));
   Edit2.Text := FloatToStr(r / 1000);
 
-
-
 end;
 
 
diff --git "a/Excercise/\353\252\250\353\223\21012/Exercise3/Unit_ch12_3.pas" "b/Excercise/\353\252\250\353\223\21012/Exercise3/Unit_ch12_3.pas"
index 288f65f..05d6392 100644
--- "a/Excercise/\353\252\250\353\223\21012/Exercise3/Unit_ch12_3.pas"
+++ "b/Excercise/\353\252\250\353\223\21012/Exercise3/Unit_ch12_3.pas"
@@ -32,7 +32,7 @@ procedure TForm1.Button1Click(Sender: TObject);
 begin
   Cnt := 0;
   s := Edit1.Text;
-  for i := 0 to Length(s) do
+  for i := 1 to Length(s) do
     if s[i] =  '.' then
        Cnt := Cnt + 1;
    ShowMessage(InTtoStr(Cnt));