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Q72540: Calculator Does Not Reliably Subtract Two Numbers in Windows

Article: Q72540
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:3.0,3.0a,3.1,3.11
Operating System(s): 
Keyword(s): 
Last Modified: 29-OCT-1999

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The information in this article applies to:

- Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 
- Microsoft Windows for Workgroups versions 3.1, 3.11 
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SYMPTOMS
========

Microsoft Windows Calculator (CALC.EXE) does not reliably subtract two numbers
with decimal values. This problem occurs in both modes (standard and scientific)
of Calculator.

CAUSE
=====

Calculator does not round the decimal values properly. While Calculator is
determining how to display the solution, it encounters a loss of precision and
shows an incorrect answer.

RESOLUTION
==========

Windows 3.0
-----------

Microsoft has confirmed this to be a problem in Windows 3.0.

Windows 3.1x, Windows for Workgroups 3.1x
-----------------------------------------

To correct this problem in Windows 3.1x and Windows for Workgroups 3.1x, obtain
the updated CALC.EXE file from the Microsoft Web site.

MORE INFORMATION
================

Steps to Reproduce Problem
--------------------------

1. Start Calculator.

2. Input the largest number to subtract first (for example, 12.52).

3. Press the MINUS SIGN (-) key on the numeric keypad.

4. Input the smaller number that is one unit lower in the decimal portion (for
  example, 12.51).

5. Press the EQUAL SIGN (=) key on the numeric keypad.

Subtracting 12.51 from 12.52 results in one of the following incorrect numbers:

  0.00
  0.0099999999
  0.010000001

Additional query words: 3.0 3.00 3.1 3.10 subtraction 3.11 appnote

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Keywords          :  
Technology        : kbAudDeveloper kbWin3xSearch kbWFWSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311 kbWFW310 kbWFW311
Version           : WINDOWS:3.0,3.0a,3.1,3.11

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