Fixed Divide:
-Found error when trying to divide by a number that goes evenly into focus. Received "Error: Answer negative"
   -Fixed by adding || sum.equals(focus) to while loop test
-Found error when number being divided had a zero at the end. The zero gets cut off by making a new Number on reverse
   -Fixed by adding a addLeadingZero method that changes the array of a number without using the constructor