87 times 30 is 2610, but what is the answer if both 87 and 30 are negative numbers? Here we will determine if the answer to negative 87 times negative 30 is positive 2610 or negative 2610.
There are many different ways to explain and determine if the answer to negative 87 times negative 30 is -2610 or +2610 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 -2610 is the correct answer using basic algebra.
We will test if -2610 is correct by setting up the equation negative 87 times negative 30 equals negative 2610, and then simplifying the equation to see if it is true.
(-87) (-30) = (-2610)
Divide both sides of the equation by (-30) :
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| = |
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The numerator and denominator on the left side both have (-30) which even each other out and can be removed:
| (-87) = |
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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:
| (-87) = |
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A numerator of 2610 and denominator of 30 on the right side is the same as 2610 divided by 30 which is 87. Now we end up with this untrue equation:
(-87) = (87)
-87 is NOT equal to 87, thus we have proven that negative 87 times negative 30 is not equal to -2610. The answer must therefore be 2610:
-87 x -30 = 2610
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 87 times negative 30 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 87 times negative 31?
Here is the next problem on our list that we have explained and calculated.
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