1 times 15 is 15, but what is the answer if both 1 and 15 are negative numbers? Here we will determine if the answer to negative 1 times negative 15 is positive 15 or negative 15.
There are many different ways to explain and determine if the answer to negative 1 times negative 15 is -15 or +15 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 -15 is the correct answer using basic algebra.
We will test if -15 is correct by setting up the equation negative 1 times negative 15 equals negative 15, and then simplifying the equation to see if it is true.
(-1) (-15) = (-15)
Divide both sides of the equation by (-15) :
|
| = |
|
The numerator and denominator on the left side both have (-15) which even each other out and can be removed:
| (-1) = |
|
The numerator and denominator on the right side both have a minus sign (-) which even each other out and can be removed:
| (-1) = |
|
A numerator of 15 and denominator of 15 on the right side is the same as 15 divided by 15 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 15 is not equal to -15. The answer must therefore be 15:
-1 x -15 = 15
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 1 times negative 15 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 16?
Here is the next problem on our list that we have explained and calculated.
Copyright | Privacy Policy | Disclaimer | Contact