small excel coding

Job ID: 35134189

Budget: $10 – $30 CAD

I need a very short excel sheet. on the sheet I need few titles including:
current quantity
name of item
changes
on the next row, lets assume that we have item A with initial quantity of 23 . every time that I put a number on changes cell I need the quantity changes to "previous amount-changes" and the new "chenges" amount become 0 again