Help required in Power BI for running total based on value passed

Hi Team,

I'm trying to do a running total for a column where I am supposed to add the column values based on the value passed.

Demand value= 73593                                                                In excel we have used offset to get this value:                     

value passed =4                                                                          Cumulative sum           '=SUM(OFFSET(B1,1,0,4,1))

Sum of 4 rows value =126463                                                     Cumulative Average    '=Average(OFFSET(B1,1,0,4,1))

In Excel, we can get this value by just passing how many rows have to get the sum, but in Power BI I couldn't get that.

In the below example Required value is showing 126463 which is the sum of 4 rows based on the value passed is 4. 

Suppose the value passed is 5 then it has to get a sum of 5 rows as the required value, where I could change the sum dynamically.

I hope someone would have come across this type of requirement. I need your help in getting the desired results.