Adding values from one month to another

[ola1996]

Hello, 

I would like to ask you how I can add values from one month to another in Power BI, frequency is 3 months.

I have data for all months and I want to see some kind of forecast but prepare it manualy. I have revenue and I want to see it in this way:

January 5000$

February 1000$

March 3000$

April =January+data from April (12000$)

May =February+data from May (1000$)

June=March +data form June (12000$)

...

[amitchandak]

@ola1996 , with help from date table, try like these examples

Rolling 4 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date ],MAX(Sales[Sales Date]),-4,MONTH))
Rolling 4 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date ],MAX('Date'[Date ]),-4,MONTH))

Rolling 4 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date ],eomonth(MAX('Date'[Date ]),0),-4,MONTH))

[ola1996]

It is not working correctly. I need to sum data from first month with data from the third one. 

January 5000$

February 1000$

March 3000$

April =January+data from April (12000$)

May =February+data from May (1000$)

June=March +data form June (12000$)

July = April +data from July 

August =May +data from August 

September = June +data from June 

October  = July + data from October

November = August +data from November 

December = September +data from December