54 times 7 is 378, but what is the answer if both 54 and 7 are negative numbers? Here we will determine if the answer to negative 54 times negative 7 is positive 378 or negative 378.
There are many different ways to explain and determine if the answer to negative 54 times negative 7 is -378 or +378 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 -378 is the correct answer using basic algebra.
We will test if -378 is correct by setting up the equation negative 54 times negative 7 equals negative 378, and then simplifying the equation to see if it is true.
(-54) (-7) = (-378)
Divide both sides of the equation by (-7) :
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| = |
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The numerator and denominator on the left side both have (-7) which even each other out and can be removed:
| (-54) = |
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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:
| (-54) = |
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A numerator of 378 and denominator of 7 on the right side is the same as 378 divided by 7 which is 54. Now we end up with this untrue equation:
(-54) = (54)
-54 is NOT equal to 54, thus we have proven that negative 54 times negative 7 is not equal to -378. The answer must therefore be 378:
-54 x -7 = 378
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 54 times negative 7 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
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