sorry it is not subtraction. output will be sometging like this 115-80

And Macropod, based on the requirement I will not need to have these two conditions. Thank you for taking a look at my question.

{If FieldA >= 140 {If FieldB>=90 " FieldA-FeildB"}
{If FieldA < 140 {If FieldB<90 "FieldA-FeildB"}
{If FieldA<120 {If FieldB <80 "FieldA-FeildB"}}

i did something like this but did not work