9 times 70 is 630, but what is the answer if both 9 and 70 are negative numbers? Here we will determine if the answer to negative 9 times negative 70 is positive 630 or negative 630.
There are many different ways to explain and determine if the answer to negative 9 times negative 70 is -630 or +630 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 -630 is the correct answer using basic algebra.
We will test if -630 is correct by setting up the equation negative 9 times negative 70 equals negative 630, and then simplifying the equation to see if it is true.
(-9) (-70) = (-630)
Divide both sides of the equation by (-70) :
|
| = |
|
The numerator and denominator on the left side both have (-70) which even each other out and can be removed:
| (-9) = |
|
The numerator and denominator on the right side both have a minus sign (-) which even each other out and can be removed:
| (-9) = |
|
A numerator of 630 and denominator of 70 on the right side is the same as 630 divided by 70 which is 9. Now we end up with this untrue equation:
(-9) = (9)
-9 is NOT equal to 9, thus we have proven that negative 9 times negative 70 is not equal to -630. The answer must therefore be 630:
-9 x -70 = 630
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 9 times negative 70 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 9 times negative 71?
Here is the next problem on our list that we have explained and calculated.
Copyright | Privacy Policy | Disclaimer | Contact