Editing Calculator (section)

====Numeric representation====
{{Main|Binary-coded decimal}}

Most pocket calculators do all their calculations in [[Binary-coded decimal|binary-coded decimal (BCD)]] rather than binary.  BCD is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use a series of separate identical [[seven-segment display]]s to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing to such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to a simpler overall system than converting to and from binary. (For example, [[CD]]s keep the track number in BCD, limiting them to 99 tracks.)

The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature BCD arithmetic modes, which assist when writing routines that manipulate BCD quantities.<ref>{{cite web |author=University of Alicante |title=A Cordic-based Architecture for High Performance Decimal Calculations |url=http://rua.ua.es/dspace/bitstream/10045/11826/1/VF-016519.pdf |publisher=[[IEEE]] |access-date=2015-08-15 |url-status=live |archive-url=https://web.archive.org/web/20160303235832/http://rua.ua.es/dspace/bitstream/10045/11826/1/VF-016519.pdf |archive-date=2016-03-03 }}</ref><ref>{{cite web |title=Decimal CORDIC Rotation based on Selection by Rounding: Algorithm and Architecture |url=http://faculties.sbu.ac.ir/~jaberipur/Papers/Journals/19.pdf |archive-url=https://web.archive.org/web/20160304045707/http://faculties.sbu.ac.ir/~jaberipur/Papers/Journals/19.pdf |archive-date=2016-03-04 |url-status=live |publisher=[[British Computer Society]] |access-date=2015-08-14}}</ref>

Where calculators have added functions (such as square root, or [[trigonometric functions]]), software [[algorithm]]s are required to produce high precision results. Sometimes significant design effort is needed to fit all the desired functions in the limited memory space available in the calculator [[Chipset|chip]], with acceptable calculation time.<ref>{{cite web |url=http://www.hpl.hp.com/hpjournal/72jun/jun72a2.pdf |title=David S. Cochran, ''Algorithms and accuracy in the HP35'', ''Hewlett Packard Journal'', June 1972 |access-date=2013-10-03 |url-status=live |archive-url=https://web.archive.org/web/20131004225515/http://www.hpl.hp.com/hpjournal/72jun/jun72a2.pdf |archive-date=2013-10-04 }}</ref>