15 times 12 is 180, but what is the answer if both 15 and 12 are negative numbers? Here we will determine if the answer to negative 15 times negative 12 is positive 180 or negative 180.
There are many different ways to explain and determine if the answer to negative 15 times negative 12 is -180 or +180 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 -180 is the correct answer using basic algebra.
We will test if -180 is correct by setting up the equation negative 15 times negative 12 equals negative 180, and then simplifying the equation to see if it is true.
(-15) (-12) = (-180)
Divide both sides of the equation by (-12) :
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| = |
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The numerator and denominator on the left side both have (-12) which even each other out and can be removed:
| (-15) = |
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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:
| (-15) = |
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A numerator of 180 and denominator of 12 on the right side is the same as 180 divided by 12 which is 15. Now we end up with this untrue equation:
(-15) = (15)
-15 is NOT equal to 15, thus we have proven that negative 15 times negative 12 is not equal to -180. The answer must therefore be 180:
-15 x -12 = 180
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 15 times negative 12 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
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