place variable in box you adjusted by performing operation

[cesardefez]

Hello community
When in the adjustment box I want to add the value of a variable, it is impossible for me to perform operations with it.

As seen in the photo, I want to multiply (* index_recovery), but when I insert this variable, it doesn't let me add the "*".
How can it be done?

thanks

[roar]

@cesardefez just do it like in the upper picture, its fine.

[cesardefez]

thanks. I will do tests. Thanks a lot