Microsoft KB Archive/124345

Updated Calculator Accessory for Windows

Q124345

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The information in this article applies to:

• Microsoft Windows versions 3.1, 3.11
• Microsoft Windows for Workgroups versions 3.1, 3.11

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Introduction

The WW1138.EXE file contains an updated version of the Calculator accessory that is shipped with Microsoft Windows 3.1x and Windows for Workgroups 3.1x. Previous versions of Calculator display simple subtraction errors when you subtract two numbers that include values to the right of the decimal point. While Calculator is determining how to display the solution, it encounters a loss of precision and shows an incorrect answer.

NOTE: This rounding error is unrelated to the floating-point unit (FPU) in the Intel(R) Pentium(R) chip. This problem occurs only in Calculator and does not affect Windows, other components in Windows, or other Windows-based applications.

In addition to correcting the problem described above, the new rounding algorithm in Calculator causes it to perform more like most hand-held calculators. For example, if you enter the following equation in the updated Calculator accessory or in a hand-held calculator

[(1/3 + 10 - 10) x 3]

the result is 0.9999. The result in previous versions of Calculator is 1.0. The value 0.9999 is generated because significant digits are lost by adding and subtracting 10. This is a secondary effect of the changes made in Calculator to correct the precision errors.

To install the updated files

The following file is available for download from the Microsoft Download Center:

Download Ww1138.exe now]

For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base:

Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. Once posted, the file is housed on secure servers that prevent any unauthorized changes to the file.

1. Download the WW1138.EXE file from the Microsoft Download Center to an empty folder.
2. Double-click the WW1138.EXE file you downloaded in step 1.
3. Quit Windows, or open an MS-DOS command prompt within Windows.

4. Rename the existing CALC.EXE file in your Windows directory. For example, if Windows is installed in a directory on drive C called WINDOWS, type the following commands, pressing ENTER after each line:

   cd\windows
   ren calc.exe calc.old

5. At an MS-DOS command prompt, type the following and press ENTER

   copy <source>:\calc.exe <location>

   where <source> is the directory containing the file you downloaded from online services, and <location> is the path to your Windows directory.
   
   For example, if you downloaded the WW1138.EXE file from online services to C:\DOWNLOAD and C:WINDOWS is the path to your Windows directory, type:

   copy c:\download\calc.exe c:\windows

Steps to Reproduce Problem Using Previous Versions of Calculator

1. To perform this test, choose two numbers that include values to the right of the decimal point (for example, 12.52 and 12.51).
2. Double-click the Calculator icon in the Accessories group.
3. Enter the larger number first (for example, 12.52).
4. Press the MINUS SIGN (-).
5. Enter the smaller number (for example, 12.51).
6. Press the EQUAL SIGN (=).

Note that in this example you do not receive .01, the expected result. Instead, you receive one of the following:

0.00

0.0099999999

0.010000001

The updated Calculator accessory displays the correct result, which is .01.

Additional query words:

Keywords : kbfile win31 kbgraphxlinkcritical
Issue type : kbinfo
Technology : kbAudDeveloper kbWin3xSearch kbWFWSearch kbWin310 kbWin311 kbWFW310 kbWFW311

Last Reviewed: June 13, 2001 © 2001 Microsoft Corporation. All rights reserved. Terms of Use.