I want to be able to input plain numbers like 200, or 3000 and have the cell display 200g, 3kg, etc... But still be able to add the values in the cells. So if I add the two above I'd get 3.2kg on the result cell. I suspect this is not possible, but is it?
Does not manage the automatic division by 1000 for kilogrammes but perhaps of some use (better than nothing?)
In New Google Sheets, Format > Number > More Formats > Custom Number Format and Apply: