13 times 1 is 13, but what is the answer if both 13 and 1 are negative numbers? Here we will determine if the answer to negative 13 times negative 1 is positive 13 or negative 13.
There are many different ways to explain and determine if the answer to negative 13 times negative 1 is -13 or +13 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 -13 is the correct answer using basic algebra.
We will test if -13 is correct by setting up the equation negative 13 times negative 1 equals negative 13, and then simplifying the equation to see if it is true.
(-13) (-1) = (-13)
Divide both sides of the equation by (-1) :
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| = |
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The numerator and denominator on the left side both have (-1) which even each other out and can be removed:
| (-13) = |
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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:
| (-13) = |
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A numerator of 13 and denominator of 1 on the right side is the same as 13 divided by 1 which is 13. Now we end up with this untrue equation:
(-13) = (13)
-13 is NOT equal to 13, thus we have proven that negative 13 times negative 1 is not equal to -13. The answer must therefore be 13:
-13 x -1 = 13
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 13 times negative 1 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
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