Book 26, Question 73
Why are phone keypads and calculators laid out in opposite orders?
Calculators copied the layout of old adding machines.
On most phones, 1-2-3 are on the top row, but on calculators and computer number pads, 7-8-9 are on top. In the early 1960s, researchers tested layouts and chose the one that people could dial quickly. Both layouts work, and people learn whichever one they use often. Old habits can be hard to change.