=day(today()) number to use in expression

[ugurarslan]

Dear all,

I need to create a set expression where I need to look at data less than day number today.

The normal expression looks like this:

Sum({<[AR Day Nbr]={'<17'},[Event]={'APP'},[Cash App Type]={'CASH'}>} [AR USD]*(-1))

I need to automate this process with looking to AR day NBR '< day(today()).

I tried 

Sum({<[AR Day Nbr]={'< day(today())'},[Event]={'APP'},[Cash App Type]={'CASH'}>} [AR USD]*(-1))

but didn't work. 

Please help me.

Thanks

Ugur

[dplr-rn]

Try
[AR Day Nbr]={"< $(day(today()))"}

[sunny_talwar]

I think you might have missed an equal sign
[AR Day Nbr]={"<$(=Day(Today()))"}

[dplr-rn]

thanks