A Calculator’s Most Important Button Has Been Removed

I worry that the calculator we’ve known and loved is not long for this Earth. This month, when I upgraded my iPhone to the latest operating system, iOS 18, it came with a refreshed Calculator app. The update offered some improvements! I appreciated the vertical orientation of its scientific mode, because turning your phone sideways is so 2009; the continuing display of each operation (e.g., 217 ÷ 4 + 8 ) on the screen until I asked for the result; the unit-conversion mode, because I will never know what a centimeter is. But there also was a startling omission: The calculator’s “C” button—the one that clears input—was gone. The “C” itself had been cleared.

Until today, the iPhone’s calculator mimicked the buttons of its forebears: If you keyed in 48.375 , for instance, instead of 43.875 , tapping “C” within your app would zero out your entry so you could try again. “Forty-three point eight seven five,” you might say aloud to remember, and then again while you tried to press the buttons in their proper order. Now that zeroing function is no more. In place of “C,” the app provides a backspace button (⌫). Pressing it removes the last digit from your input: 48.375 becomes 48.37 , then 48.3 , and so on. This may seem like an insignificant development, or a minor change for the better. Instead of clearing an errant figure and then incanting its digits while trying to reenter them, I can simply reverse to the point where I made the error—backspace, backspace, backspace—and type again from there, just as I’d do for text. By all measures of reason, this process is superior. Yet the loss of “C” from my calculator app has been more than a shock to me. It feels like an affront.

The “C” button’s function is vestigial. Back when calculators were commercialized, starting in the mid-1960s, their electronics were designed to operate as efficiently as possible. If you opened up a desktop calculator in 1967, you might have found a dozen individual circuit boards to run and display its four basic mathematical functions. Among these would have been an input buffer or temporary register that could store an input value for calculation and display. The “C” button, which was sometimes labeled “CE” (Clear Entry) or “CI” (Clear Input), provided a direct interface to zero out—or “clear”—such a register. A second button, “AC” (All Clear), did the same thing, but for other parts of the circuit, including previously stored operations and pending calculations. (A traditional calculator’s memory buttons—“M+,” “M-,” “MC”—would perform simple operations on a register.)

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