Create small "drill down" displaced ranges for quick sums, subtracions, etc
I worked with old time accountants that would add numbers on the side and then key them into worksheets creating cursed mystery numbers lacking any reference in the worksheet they created thus also creating a nightmare for future users
So I've always thought it would be nice to be able to have an option of creating a mini sheet within a sheet (a quick automatic link to a range in another tab containing quick calcs). So maybe entering two equal signs ( == or something) a two or three column 10 line pop up grid would appear. Users could plug in their numbers and any simple references and this information would be saved somewhere else (say a tab dedicated to such little side calculations). Naturally, just the formula and/or result would appear in the cell itself just as with say =10+20+30. Instead maybe it would look like ==[link] or =a10+a50-[link]
I know notes can be entered following a formula with a colon or something I believe. (Havent used it in years)
Kenneth Barber commented
You can use a normal sheet for side calculations! I don't see any reason to have a special type of sheet. I can also see the problem of people wanting to reclassify "quick" calculations as permanent calculations.