40 times 41 is 1640, but what is the answer if both 40 and 41 are negative numbers? Here we will determine if the answer to negative 40 times negative 41 is positive 1640 or negative 1640.
There are many different ways to explain and determine if the answer to negative 40 times negative 41 is -1640 or +1640 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 -1640 is the correct answer using basic algebra.
We will test if -1640 is correct by setting up the equation negative 40 times negative 41 equals negative 1640, and then simplifying the equation to see if it is true.
(-40) (-41) = (-1640)
Divide both sides of the equation by (-41) :
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| = |
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The numerator and denominator on the left side both have (-41) 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 1640 and denominator of 41 on the right side is the same as 1640 divided by 41 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 41 is not equal to -1640. The answer must therefore be 1640:
-40 x -41 = 1640
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 40 times negative 41 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 42?
Here is the next problem on our list that we have explained and calculated.
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