{$n+}
uses crt;
var
  a,b:extended;
  ch:char;
  flag:boolean;

Begin
  repeat
  flag:=True;
  clrscr;
  write('Vvedite pervoe 4slo : ');
  readln(a);
  write('Vvedite vtoroe 4islo : ');
  readln(b);
  write('Vvedite deistvie < +, - , * , / > : ');
  ch:=readkey;
  case ch of
     '+': writeln(a:2:2,'+',b:2:2,'=',a+b:2:2);
     '-': writeln(a:2:2,'-',b:2:2,'=',a-b:2:2);
     '*': writeln(a:2:2,'*',b:2:2,'=',a*b:2:2);
     '/': if b<> 0 then writeln(a:2:2,'/',b:2:2,'=',a/b:2:2)
            else writeln('Div by zero')
     else writeln('Err');
  end;

  write('Exit ? <Y/N>');
  ch:=readkey;

  if ch='y' then flag:=false;

  until not(flag);
  end.