What is negative 17 times negative 20? (-17 x -20)

What is negative 17 times negative 20?

17 times 20 is 340, but what is the answer if both 17 and 20 are negative numbers? Here we will determine if the answer to negative 17 times negative 20 is positive 340 or negative 340.

There are many different ways to explain and determine if the answer to negative 17 times negative 20 is -340 or +340 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 -340 is the correct answer using basic algebra.

We will test if -340 is correct by setting up the equation negative 17 times negative 20 equals negative 340, and then simplifying the equation to see if it is true.

(-17) (-20) = (-340)

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

		(-17) (-20)
		(-20)

		(-340)
		(-20)

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

(-17) =

		(-340)
		(-20)

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

(-17) =

		(340)
		(20)

A numerator of 340 and denominator of 20 on the right side is the same as 340 divided by 20 which is 17. Now we end up with this untrue equation:

(-17) = (17)

-17 is NOT equal to 17, thus we have proven that negative 17 times negative 20 is not equal to -340. The answer must therefore be 340:

-17 x -20 = 340

The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 17 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 17 times negative 21?
Here is the next problem on our list that we have explained and calculated.