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Adding a Negative Number

Date: 3/19/96 at 10:21:44
From: Anonymous
Subject: Suggestion Box

Comments: How do you solve 123 + (-43) ?

Date: 3/19/96 at 20:18:54
From: Doctor Patrick
Subject: Re: Suggestion Box

Hi Mike.  

Adding a negative number is exactly the same as subtracting a 
positive number.  In your example, 123 + (-43) is the same as 
123 - 43. 

Think of it this way -
If you had $123 and I gave you a bill for $43, how much would 
you have?  

You would have to subtract the $43 from the $123 to get your 
answer - you would be adding a -$43 to what you had, or $80.

Hope this helps,

-Doctor Patrick,  The Math Forum

Associated Topics:
Middle School Number Sense/About Numbers

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