What is negative 1 times negative 20? (-1 x -20)

What is negative 1 times negative 20?

1 times 20 is 20, but what is the answer if both 1 and 20 are negative numbers? Here we will determine if the answer to negative 1 times negative 20 is positive 20 or negative 20.

There are many different ways to explain and determine if the answer to negative 1 times negative 20 is -20 or +20 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 -20 is the correct answer using basic algebra.

We will test if -20 is correct by setting up the equation negative 1 times negative 20 equals negative 20, and then simplifying the equation to see if it is true.

(-1) (-20) = (-20)

Divide both sides of the equation by (-20) :

		(-1) (-20)
		(-20)

		(-20)
		(-20)

The numerator and denominator on the left side both have (-20) which even each other out and can be removed:

(-1) =

		(-20)
		(-20)

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

(-1) =

		(20)
		(20)

A numerator of 20 and denominator of 20 on the right side is the same as 20 divided by 20 which is 1. Now we end up with this untrue equation:

(-1) = (1)

-1 is NOT equal to 1, thus we have proven that negative 1 times negative 20 is not equal to -20. The answer must therefore be 20:

-1 x -20 = 20

The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 1 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 1 times negative 21?
Here is the next problem on our list that we have explained and calculated.