Divide formula filtering through specific time periods

[bgonen7]

I have the formula below that works fine when I check the filter : "Revised cleared periods" 

the formula goes like this:

Avg Receipts =

 DIVIDE( SUMX('Open AR',[$Group amount]*[Arrears]),SUM([AMOUNT_GROUP_CURR]))

All I am trying to do is to add to this formula to filter through most recent 3 months of the column "Revised cleared periods" from the Table: 'Open AR'

[bgonen7]

Thanks for the quick response.

var _max showed no errors but when integrating with var _min it reflected an error.

Anyway, I got an alternate solution (but I might go back to your solution at some point).

[amitchandak]

@bgonen7 , You need create a measure like

example

3 Months=
var _max = maxx(allselected(date),date[date]) // or today()
var _min = date(year(_max), month(_max)-3,1)
return
CALCULATE([Avg Receipts],filter(date, date[date] <=_max && date[date] >=_min))