title: QuickSight - Calculate sum of difference between months
body: <p>I need to calculate the sum of bad debt and recovery in a given period. The field difference is calculated with the formula and the bad debit and recovery with if greater or lesser than zero. When I try to add by sum it gives an invalid reference</p>
  <p><a href="https://i.stack.imgur.com/2Vm0x.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2Vm0x.png" alt="enter image description here" /></a></p>