How to do simple calculation (1 - Item's Number) in backend workflows

[tom29]

I’m struggling to do a simple calculation in a backend workflow: Item A = 1 - Item B’s Number

After typing in the “1” is does not seem to be possible to add a math operator like “-”?

Things I tried:

• I already have the New Expression Composer activated. Seems to make no difference.
• I tried using plugins like math.js or toolbox but apparently can’t be used in backend workflows.

Any help would be appreciated. Surely this is a simple problem so it’s weird I’m struggling with this…

[yamada.shoji99]

If the data type is a number, the operation should appear

[mikeloc]

You can’t start an expression with a number like that. One way you can get what you want is to set a custom state (number) to 1, and then you can build the expression custom state's value - Item B's number.

Edit: I just noticed you said a backend workflow, and you should be able to use a parameter (set to a value of 1) in the expression.

[tom29]

Hi Mike,

Your suggestion to set a parameter of the backend workflow to 1 is brilliant, that works perfectly!

In the meantime I also found 2 alternatives (which are not as good as yours though):

1. Start the expression with Arbitrary text :converted to number where Arbitrary text is equal to 1
2. Re-arragne the formula to Item B's number*-1 + 1