HP 20S recurring key identification


Just wondering how to enter a recurring number without hitting the last digit several times. Thanks.


Just wondering how to enter a recurring number without hitting the last digit several times.


Did you mean the HP-20S, and not the HP-20b, correct?

Also, by "recurring number", did you mean a constant value used for repeated calculations, or a repeating-sequence fractional part of a number?

I don't see a constant-operand key or capability on the HP-20S or in its manual.

-- KS

Edited: 22 Nov 2010, 9:51 p.m.


I've never come across a recurring decimal facility on any calculator, except for a couple of new Casio models (e.g., FX-83 GT Plus). I'm sure that no HP model has this facility. Does anyone know differently?


If it is a repeating fractional part of a number, you may enter it as a fraction. Suppose x=0.2977777... 10x = 2.977777... 9x = 2.68 x=2.68/9 This is "a recurring number without hitting the last digit several times" /Tommy


I have a Bohn Omnitrex 8 desktop calculator. Its extremely simple logic using DTL chips doens't implement any sort of decimal point. The way it does division is to simply show a "running quotient", meaning that it only stores the remainder and the divisor and just keeps going. Because of this it allows infinitely long quotients and therefore, in some sense, recurring decimals.

For example if you divide 1 by 7 and keep hitting the "=" key you'll see: 142857142857........ If you give it something with a larger period like 1 divided by 181 you'll see: 005524861878........ and it will keep going for 180 digits then repeat.

It's pretty neat, very primitive and the only calculator that I've ever come across that does this.


Edited: 22 Nov 2010, 1:53 p.m.


That's really nice logic - never heard of any calculator like this before. Thanks for pointing to that.

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