If there's not a single correct answer, in other words, one guess is as good as another, why teach math at all? That would save a lot of time (as if there's a way to measure time!!!) and everybody would feel equally good about themselves, which apparently is the point.
We should have seen this coming. It's been there, right in front of us, for years. Now that everyone has a calculator, or a cell phone that plays calculator upon request, and stores all have registers that calculate change, clerks (sorry -- "associates") don't have to figure out or count change any more. I'm not the only one here who has commented on the phenomenon. Suppose you're in a store and your bill rings up as $19.06. You hand the cashier a twenty, a nickle, and a penny. The cashier than stands there for ten minutes, staring at the six cents and wondering why that stupid old man gave me coins when all he needs is change for a twenty.
Then they finally get around to punching $20.06 into the "Amount tendered" box, and the look on their faces when the change rings up to an even one dollar is priceless. It's like "Magic! How did he do that?"