What is negative 90 times negative 89? (-90 x -89)

What is negative 90 times negative 89?

90 times 89 is 8010, but what is the answer if both 90 and 89 are negative numbers? Here we will determine if the answer to negative 90 times negative 89 is positive 8010 or negative 8010.

There are many different ways to explain and determine if the answer to negative 90 times negative 89 is -8010 or +8010 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 -8010 is the correct answer using basic algebra.

We will test if -8010 is correct by setting up the equation negative 90 times negative 89 equals negative 8010, and then simplifying the equation to see if it is true.

(-90) (-89) = (-8010)

Divide both sides of the equation by (-89) :

		(-90) (-89)
		(-89)

		(-8010)
		(-89)

The numerator and denominator on the left side both have (-89) which even each other out and can be removed:

(-90) =

		(-8010)
		(-89)

The numerator and denominator on the right side both have a minus sign (-) which even each other out and can be removed:

(-90) =

		(8010)
		(89)

A numerator of 8010 and denominator of 89 on the right side is the same as 8010 divided by 89 which is 90. Now we end up with this untrue equation:

(-90) = (90)

-90 is NOT equal to 90, thus we have proven that negative 90 times negative 89 is not equal to -8010. The answer must therefore be 8010:

-90 x -89 = 8010

The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 90 times negative 89 will always have a positive answer.

Negative Times Negative Calculator
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