inventory running count

here is the updated sheets I am working in:

My sheet is refined some and hopefully a little clearer as to what I am trying to do. basically on sheet 3 in the GREEN boxes is my begining number. In the Blue boxes I would like to add to the green box. In the Red box I would like to subtract from the current number (green box). the yellow box represents the current running total, which is also shown on sheet 2.

Hopefully this makes sense, everytime I try what I think is right after a few adding and subtracting numbers it does not add up correctly. If the green box is a problem I can do away with it.

Any help is appreciated