in 'update' sheet, F column, the current value of quantity should be added with value in 'IN' sheet, D column.
in 'IN' sheet if i choose an item from dropbox (c column) and put quantity of 10, then it should be added with the current value in 'UPDATE' column F sheet for the same named item. i tried this formula (this is nonsense formula come to my head) but fail in 'update!f7, sheet =f7+(vlookup,purchase,2,false) thank you in advance
