Structure formula to show difference between two % figures

[Lean Li]

I am trying to find a way to present the difference between current progress% and previous progress % (in a custom field) with a structure formula.

Currently I have  this formula for a percentage column;

if Progress and Previous_progress: (Progress/Previous_progress)/100

But the problem is that for example in a case when the

• previous progress is 60 %
• current progress is 60 %

-> formula returns 1%  and what I would want it to return is 0%

And in a case when:

• previous progress is 60 %
• current progress is 65 %

-> the formula should return 5%  

Any ideas on how to solve this would be greatly appreciated!

[Lean Li]

This was solved with formula:

IF Progress and Previous_progress : (Progress-Previous_progress) 

I thought the minus-function is not supported but it works very well, so this question was invalid in the first place.