Subtracting from different table with each have IDs

[YSU_IT_DEPT]

Good day, I would like to ask how to subtract two different tables each having IDs related to each other. 
the problem is table 1 and 2 has many to one relationship, I want to know how to get the total value of the specific id for table 1 and subtract it to the table 2 with same id 

example table below

table 1 has 3 row with the same document no
table 2 has 1 row only

what I want to know is to how to make a meassure that will add up all the value from table 1 then subtract it with the table 2 value then show it on a matrix table

[YSU_IT_DEPT]

this is the matrix setup

if I will be able to subtract Table 2 to Table 1 the total will be complete