Background
Calculators are not only to make basic computations but can also have scientific functions, conversion functions, drawing functions, etc.
Recommendation
We like to recommend the PowerToy Calc from Microsoft. It does everything you’d expect from a calculator although you have to type your operations rather than dial them on a keypad as you can with other calculators.
For those who find this tool a bit too complicated and prefer a dialpad then we recommend simply the default calculator in Windows. In windows 7 the calculator is much improved and this new calculator can be used on Vista as well.
As for Windows XP you may want to install Calculator Plus from Microsoft, which adds some functions, conversion especially, to the standard XP calculator which has only basic and scientific modes.
Web links
PowerToy Calc
Web site: http://www.microsoft.com/windowsxp/Downloads/powertoys/Xppowertoys.mspx
Windows 7 calculator for Vista
Web site: http://www.askvg.com/get-windows-7-calculator-working-in-windows-vista/
Calculator Plus
Web site: http://www.microsoft.com/downloads/thankyou.aspx?familyId=32b0d059-b53a-4dc9-8265-da47f157c091&displayLang=en
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