40 times 55 is 2200, but what is the answer if both 40 and 55 are negative numbers? Here we will determine if the answer to negative 40 times negative 55 is positive 2200 or negative 2200.
There are many different ways to explain and determine if the answer to negative 40 times negative 55 is -2200 or +2200 using mathematical terms such as additive inverse and mathematical laws like the Distribute Law.
We will take a different approach - process of elimination: We will simply test if -2200 is the correct answer using basic algebra.
We will test if -2200 is correct by setting up the equation negative 40 times negative 55 equals negative 2200, and then simplifying the equation to see if it is true.
(-40) (-55) = (-2200)
Divide both sides of the equation by (-55) :
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| = |
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The numerator and denominator on the left side both have (-55) which even each other out and can be removed:
| (-40) = |
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The numerator and denominator on the right side both have a minus sign (-) which even each other out and can be removed:
| (-40) = |
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A numerator of 2200 and denominator of 55 on the right side is the same as 2200 divided by 55 which is 40. Now we end up with this untrue equation:
(-40) = (40)
-40 is NOT equal to 40, thus we have proven that negative 40 times negative 55 is not equal to -2200. The answer must therefore be 2200:
-40 x -55 = 2200
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 40 times negative 55 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 40 times negative 56?
Here is the next problem on our list that we have explained and calculated.
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