find weighted average

A B D E F G H 1 J K L M Date Units Receipt Unit Cost Units Units Issues break Unit Cost down Total Cost of Issue Units Balance Total Cost Unit Cost of Inventory 2 200 $4.00 $800.00 250 250 $4.15 $4.35 3 1-Jan 4 10-Jan 5 15-Jan 6 30-Jan 7 5-Dec 8 10-Feb 300 300 $4.50 300 9