Create formula between 2 different sheets that contain a drop list

Hello,

 

I am trying to create a subtract fromula in excel sheet with no success. I am working on 2 excel sheets to do some inventory management. the first one contains a list of all the items we have in the stock followed by  column for the related quantity ordered of each items. the second sheet is for the items movement history. i have created a drop down list containing the items description with a column for the qty out for each item. i need to get the total balance for each item in the first sheet for every time i do a movement for any item in the second sheet. how the balance of any item in sheet 1 can be linked by the last movement history for the same item description in sheet 2?? you may find attached an example of what i need to know. highlighted the 2 cells in 2 different sheet that should be linked with each other in the red.

 Thank you