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I have always seen the C and CE buttons on physical calculators just as they are displayed on the Windows Calculator, but I never really understood what the abbreviations mean and what exactly is the difference between them:

Windows Calculator Picture

So, what do the abbreviations on these buttons stands for? I have never noticed any difference with using both on simple and routine calculations

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According to Vintage Technology, both buttons are a way to clear or cancel an entry. The C button will clear all input to the calculator. The CE button clears the most recent entry, so if you make a mistake in a long computation, you don't need to start all over again.

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Example

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If I now press the CE button, only the 5 is erased. The rest of my computation is still stored.

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If I press the C button, my whole computation will be cleared:

enter image description here

History

One might ask why we have these specific keys on our Windows calculator? Why are they not labeled differently?

Luckily, the guys over at Vintage Calculators have an amazing collection of information on the subject.

According to their site, the first electronic calculator was released by Bell Punch Co., Uxbridge, England in 1961. This were the Anita Mk VII and the Anita Mk 8.

Anita Mk VII

Anita Mk VII
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Anita Mk 8

Anita Mk 8
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For the Mk 8 we get an additional schema:
Schema of the Anita Mk8
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We can see it has a Clear Register and Clear Keyboard button. Please keep in mind, to my knowledge, this is one of the first electronic calculators that was ever designed.

The terminology was also used in later models, like the Sanyo ICC-0081, which seemed to have a CK (Clear Keyboard) and CA (Clear All) button.

Sanyo ICC-0081
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Later models just continue the pattern. For example, the

Canon Pocketronic

Canon Pocketronic
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We can see a C (Clear) and CI (Cancel Input) button.

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  • 6
    'C' is probably the acronym for "Clear", do you now what does the 'CE' means? – Diogo Jul 16 '12 at 18:29
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    @Diogo: "Cancel Entry" according to Vintage Technology. – Der Hochstapler Jul 16 '12 at 18:31
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    And this is extremely bad usability, btw. You cancel an entry with backspace. This confusion between "C" and "CE" (even in real world calculators) is what leads people to doubt the efficacy of the clear button leading users to press it numerous times. – Thomas Bonini Jul 16 '12 at 19:33
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    @AndreasBonini: Backspace will only remove 1 character from the input while CE will clear the whole input buffer. The difference becomes apparent when putting in long numbers. I just wanted to note that :) – Der Hochstapler Jul 16 '12 at 19:37
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    Huh, I always thought it was "Clear", and "Clear Everything". I guess I had the functions backwards! – Fake Name Jul 16 '12 at 21:32
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CE means "Clear entry" it just clears the last number typed into the display

C means "Clear" (more) It clears the display and any partial calculation.

Example: you enter 25 + 3 If you hit CE, it erases the 3, but remembers you were adding something to 25. You can now enter 8 and =, and you'll see 33.

If you hit C, it forgets the whole thing, and if you now enter 8 and =, you will see 8 still there.

MC clears the separate value stored in memory, which is not affected by C or CE.

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