Re: -+x/ or /x-+ ? Message #3 Posted by Kevin Schoedel on 11 July 2000, 4:28 p.m., in response to message #1 by Trevor Palmer
Even the earliest *desktop* calcuators used the "/x-+" pattern (HP9100), even when the corresponding handheld had "-+x/"; compare for example the HP45 vs HP46 or HP67 vs HP97. The reason for the "/x-+" order, presumably, is that the operations appear in "order of complexity" from bottom to top, with the precedent of adding-machine style keyboards with the big "+" at the bottom. I don't know the reason for the "-+x/" layout; my best guess is that it again lays out the operations in this "order of complexity", but this time from the inside out. That is, the "most important" operator, "+", is on the "home row" of the keyboard, that is, in line with the middle of the numbers, with "-" and "x" on the adjacent rows, and "/" left over at the bottom.
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