30 times 20 is 600, but what is the answer if both 30 and 20 are negative numbers? Here we will determine if the answer to negative 30 times negative 20 is positive 600 or negative 600.
There are many different ways to explain and determine if the answer to negative 30 times negative 20 is -600 or +600 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 -600 is the correct answer using basic algebra.
We will test if -600 is correct by setting up the equation negative 30 times negative 20 equals negative 600, and then simplifying the equation to see if it is true.
(-30) (-20) = (-600)
Divide both sides of the equation by (-20) :
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| = |
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The numerator and denominator on the left side both have (-20) which even each other out and can be removed:
| (-30) = |
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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:
| (-30) = |
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A numerator of 600 and denominator of 20 on the right side is the same as 600 divided by 20 which is 30. Now we end up with this untrue equation:
(-30) = (30)
-30 is NOT equal to 30, thus we have proven that negative 30 times negative 20 is not equal to -600. The answer must therefore be 600:
-30 x -20 = 600
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 30 times negative 20 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 30 times negative 21?
Here is the next problem on our list that we have explained and calculated.
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