Create a calculated pivot based on relationship of multiple table

[radian89]

Hi All,

I'd like to ask how to create a calculated pivot table based on this relationship? my goal is to create a pivot table with this columns

1. ITEM CODE [from Tbl_ListProduct]
2. PRODUCT [from Tbl_ListProduct]
3. QTY [SUM from Tbl_SalesDtbs] - based on slicers from YEAR
4. RunningRate [QTY]/12 from point number 3 - this is calculated, it divided by 12
5. QTY [ SUM from Tbl_InventoryDtbs]

I can show columns from point number 1,2,3 & 5, but for the RunningRate, i can't get the idea to create it? please help?