That's an interesting concept. I've never had to use it. I'm not a programmer, so I don't really know how they set up iterations. I just know it works.
Excel looks at the rest of a formula and then apparently starts out using trial numbers and then moves toward a result that's in the ballpark of what the equation is trying to do. If it finds a "solution," it stops and I look at it to see if it fits. Usually, it does. Sometimes Excel is stumped and I have to figure out a different approach. I depend on that feature for important stuff, so I'd rather stay with Excel than try to manufacture something. I'm just not qualified to do that. I wish Apple would make a serious effort to make Numbers a functional equivalent to Excel. MS keeps messing around with Excel to the point I don't trust them when they announce a new version. Several years ago, I spent a lot of time putting together macros that made my work much easier. It was a major investment in time. Then they eliminated the feature and told us to use Visual Basic. To me, that meant sorry, chump, your work is dead and you'll have to use Visual Basic instead. Great. I don't know how to use it and I don't have the time to learn it. I found other ways to rig the spreadsheets to do what I wanted, but I'd go back to the old way in a heartbeat if they restored the macros they once had. (end of rant) Thanks for your interest. Also, thanks again for the info regarding disk permissions. That was a huge help. Best regards.
