27 times 81 is 2187, but what is the answer if both 27 and 81 are negative numbers? Here we will determine if the answer to negative 27 times negative 81 is positive 2187 or negative 2187.
There are many different ways to explain and determine if the answer to negative 27 times negative 81 is -2187 or +2187 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 -2187 is the correct answer using basic algebra.
We will test if -2187 is correct by setting up the equation negative 27 times negative 81 equals negative 2187, and then simplifying the equation to see if it is true.
(-27) (-81) = (-2187)
Divide both sides of the equation by (-81) :
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| = |
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The numerator and denominator on the left side both have (-81) which even each other out and can be removed:
| (-27) = |
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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:
| (-27) = |
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A numerator of 2187 and denominator of 81 on the right side is the same as 2187 divided by 81 which is 27. Now we end up with this untrue equation:
(-27) = (27)
-27 is NOT equal to 27, thus we have proven that negative 27 times negative 81 is not equal to -2187. The answer must therefore be 2187:
-27 x -81 = 2187
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 27 times negative 81 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 27 times negative 82?
Here is the next problem on our list that we have explained and calculated.
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