18 times 3 is 54, but what is the answer if both 18 and 3 are negative numbers? Here we will determine if the answer to negative 18 times negative 3 is positive 54 or negative 54.
There are many different ways to explain and determine if the answer to negative 18 times negative 3 is -54 or +54 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 -54 is the correct answer using basic algebra.
We will test if -54 is correct by setting up the equation negative 18 times negative 3 equals negative 54, and then simplifying the equation to see if it is true.
(-18) (-3) = (-54)
Divide both sides of the equation by (-3) :
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| = |
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The numerator and denominator on the left side both have (-3) which even each other out and can be removed:
| (-18) = |
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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:
| (-18) = |
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A numerator of 54 and denominator of 3 on the right side is the same as 54 divided by 3 which is 18. Now we end up with this untrue equation:
(-18) = (18)
-18 is NOT equal to 18, thus we have proven that negative 18 times negative 3 is not equal to -54. The answer must therefore be 54:
-18 x -3 = 54
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 18 times negative 3 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
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