function cnum(inum){
  if(inum < 10){
    return "0000" + inum;
  } else if(inum < 100){
    return "000" + inum;
  } else if(inum < 1000){
    return "00" + inum;
  } else if(inum < 10000){
    return "0" + inum;
  } else {
    return inum;
  }
}

function openBox(num){
  num -= 100000;
  var my_answer = "answer";
  $("." + my_answer + cnum(num)).show();
}

function closeBox(num){
  num -= 100000;
  var my_answer = "answer";
  $("." + my_answer + cnum(num)).hide();
}

function allClose(){
  var my_answer = "answer";
  for(var i = 1; i <= 100; i++){
    $("." + my_answer + cnum(i)).hide();
  }
}

$(function(){ allClose(); });