SOURCE

$(document).ready(function(){
  $(".sbox1").click(function(){
    $(".sbox1").css("background-color","blue");
  })
});

$(function(){
  $(".sbox2").click(function(){
    $(".sbox2").css("background-color","blue");
  })
})

<div class="bigbox bbox1">
  <div class="smallbox sbox1">
      1
  </div>
  <div class="smallbox sbox2">
      2
  </div>
</div>
<div class="bigbox bbox2">
  <div class="smallbox sbox3">
      1
  </div>
  <div class="smallbox sbox4">
      2
  </div>
</div>

.bigbox{
  width:200px;
  height:100px;
} 
.smallbox{
  width:100px;
  height:100px;
}
.sbox1{
  float: left;
  background-color: green;
}
.sbox2{
  float: left;
  background-color: orange;
}
.sbox3{
  float: left;
  background-color: orange;
}
.sbox4{
  float: left;
  background-color: green;
}