> let numberPrimitive = 0;
  undefined
  > let numberObject = new Number(0);
  undefined
  > typeof(numberPrimitive);
  'number'
  > typeof(numberObject);
  'object'
  > typeof(numberObject + numberObject);
  'number'
  > numberPrimitive;
  0
  > numberObject;
  [Number: 0]
  > numberPrimitive.one = 1;
  1
  > numberObject.one = 1;
  1
  > numberPrimitive.one;
  undefined
  > numberObject.one;
  1
  > numberPrimitive;
  0
  > numberObject;
  [Number: 0] { one: 1 }