The Museum of HP Calculators

HP Forum Archive 19

 HP 20S recurring key identificationMessage #1 Posted by Andrew on 22 Nov 2010, 12:49 a.m. Just wondering how to enter a recurring number without hitting the last digit several times. Thanks.

 Re: HP 20S recurring key identificationMessage #2 Posted by Karl Schneider on 22 Nov 2010, 1:17 a.m.,in response to message #1 by Andrew Quote: 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.

 Re: HP 20S recurring key identificationMessage #3 Posted by Nigel J Dowrick on 22 Nov 2010, 11:30 a.m.,in response to message #1 by Andrew 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?

 Re: HP 20S recurring key identificationMessage #4 Posted by Tommy on 22 Nov 2010, 1:29 p.m.,in response to message #3 by Nigel J Dowrick 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

 Re: HP 20S recurring key identificationMessage #5 Posted by Katie Wasserman on 22 Nov 2010, 1:53 p.m.,in response to message #3 by Nigel J Dowrick 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. -Katie Edited: 22 Nov 2010, 1:53 p.m.

 Re: HP 20S recurring key identificationMessage #6 Posted by Walter B on 22 Nov 2010, 3:19 p.m.,in response to message #5 by Katie Wasserman That's really nice logic - never heard of any calculator like this before. Thanks for pointing to that.

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