How to calculate difference beetwen column

Hi,

How do i calculate diffrence between column on power BI, the column that i want to calculate like this

but the column in table between plan and actual is diffrence, I make relationship between plan vs aktual based on date and seam.

here's the plan column on table 1:

and here's the actual column on table 2:

note:

plan and actual column on different table

is that possible on power BI ?.

thankyou