title: Performing arithmetic operations on isolated arraylist elements
body: <p>I am looking for a clear <strong>explanation</strong> to my question (NOT looking for code), but if a bit of code helps to explain yourself, then please do.. thank you :)</p>
  
  <p>Question:</p>
  
  <p>-using Java
  -Main class asks user for 2 integer inputs, then places them into 2 arraylists, of type integer. Each digit is broken up and stored in its own index, so it is its own "element", so to speak.</p>
  
  <p>For example, with my code right now, it goes something like this:</p>
  
  <p>"Please enter an integer:"</p>
  
  <p>688</p>
  
  <p>"Please enter another integer:"</p>
  
  <p>349</p>
  
  <hr>
  
  <p>At this point now, internally, I have stored the input as 2 arraylists, that look like this:</p>
  
  <p>ArrayList1: [6, 8, 8]</p>
  
  <p>ArrayList2: [3, 4, 9]</p>
  
  <p>Now, lets say I want to perform some addition, such as ArrayList1 + ArrayList2.</p>
  
  <p>I'll probably go ahead and create a temporary 'result' arraylist, then move that answer over to arraylist1 when my calculation is complete.</p>
  
  <p>But the part I am having trouble with, is coming up with a systematic clear way to add the arraylists together. Keep in mind that this example uses an arraylist which represents an integer of length 3, but this could be anything. I could, for example, have an arraylist with 50 elements, such as [2, 4, 4, 3, 7, 3, 6, 3,.............] which could represent a huge number in the trillions, etc.</p>