The Museum of HP Calculators

HP Forum Archive 05

 HP-12C Rounding of periodsMessage #1 Posted by Hoang Tran on 4 Mar 2001, 9:37 p.m. Is there any way I can get the calculator to give me fractions of periods rather than having it round to the next highest period? Here is an example: Invest \$1000 at 10% annual interest. How long does it take for the the money to double? The HP will say it takes 8 years, although it really only takes seven years and change. How do I get this value displayed as 7.xxx? Thanks, Hoang.

 Re: HP-12C Rounding of periodsMessage #2 Posted by Todd Garabedian on 5 Mar 2001, 8:55 p.m.,in response to message #1 by Hoang Tran You can change the number of decimal places by pressing "f" followed by a number equivalent to the number of decimal places. For example, pressing f4 gives four places after the decimal. Pressing "f" followed by "." and then followed by a number gives scientific notation. Hope that helps. Todd

 Re: HP-12C Rounding of periodsMessage #3 Posted by Les Bell (Australia) on 5 Mar 2001, 11:37 p.m.,in response to message #1 by Hoang Tran Hoang Tran wrote: >> Invest \$1000 at 10% annual interest. How long does it take for the the money to double? The HP will say it takes 8 years, although it really only takes seven years and change. How do I get this value displayed as 7.xxx? << Problem here is your selection of compound interval. Although the interest rate is 10% per annum, it is more usually compounded monthly, i.e. i = 10%/12 = 0.83%. Now, if you repeat the calculation, you should get a result of 83.52 *months*, or just under 7 years. I would expect the 12C to have shifted functions to allow entry of annual interest rates, but compounded monthly - the various 41C pacs that do TVM all do. Best, --- Les [http://www.lesbell.com.au]

 Won't work. HP12C ALWAYS rounds "n" UPMessage #4 Posted by Gene Wright on 6 Mar 2001, 10:59 a.m.,in response to message #3 by Les Bell (Australia) The HP12C always rounds the value of N up to the next whole integer. The HP12C owners manual (or application manual) has a program that can be keyed in to provide a more "accurate" answer, but the stock HP12C cannot do this. Gene

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