You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Help Please
- Thread starter Butter
- Start date
I have a question. What is negative 2 subtract negative 2 .What are the steps to getting the answer.
Please help!
There are several ways of thinking about this problem. Here is one way: any time we subtract a number from itself, the answer is zero. For example, 5 - 5 = 0, right? So,
(-2) - (-2) = 0
Make sense?
Here is another approach: a negative of a negative is equivalent to a positive. For example, -(-5) = +5. So your problem becomes
(-2) - (-2) = (-2) + 2 = 0
Hope that helps.
HallsofIvy
Elite Member
- Joined
- Jan 27, 2012
- Messages
- 7,763
In general, by the definition of "subtraction", 'a subtract a' is equal to 0.
HallsofIvy
Elite Member
- Joined
- Jan 27, 2012
- Messages
- 7,763
I'm not sure what you are trying to say here. Yes, addition and subtraction are opposites but I don't see how "If you add -2 to -2, you get -4" has anything to do with 0.addition and subtraction are opposites: OK?
If you add -2 to -2, you get -4, right?
So, if you subtract instead, you get opposite results, thus 0 ; well?!
More appropriate would be that when you add 0 and -2 you get -2 so reversing that gives -2 subtract -2 is 0.
Negative numbers were introduced into mathematics with respect to implicit directionality. That is abstract so let's take a concrete example.I'm not sure what you are trying to say here. Yes, addition and subtraction are opposites but I don't see how "If you add -2 to -2, you get -4" has anything to do with 0.
More appropriate would be that when you add 0 and -2 you get -2 so reversing that gives -2 subtract -2 is 0.
We build a scale for temperature (the Celsius scale), where 0 is defined as the freezing point of water and 100 as the boiling point of water. Boiling occurs at a hotter temperature than feezing, and 100 is a positive number so we associate heat with positive. Obviously then we must associate cold with negative. If it is 2 degrees below zero ( which is minus 2 degrees) and it gets two degrees colder (we add minus two degrees of temperature), the resulting temperature is minus 4 degrees.
(Thank you Morris Klein.)
Bob Brown MSEE
Full Member
- Joined
- Oct 25, 2012
- Messages
- 598
We learn that dividing fractions can often be simplified by transforming the division problem into a multiplication problem.
1) We don't need "special" division rules.
2) Only need to multiply fractions.
Rule: invert and multiply.
Example: (3/4)÷(5/7) = (3/4)x(7/5)
1) Second number is inverted using multiplicative inverse.
2) Multiplicative inverse of x is 1/x
We can simplify subtraction in the same way.
1) We don't need "special" subtraction rules.
2) Only need to add signed numbers.
Rule: invert and add.
Example: (-2)-(-2) = (-2) + (2) = 0
1) Second number is inverted using additive inverse.
2) Additive inverse of n is -n (simply change the sign)
1) We don't need "special" division rules.
2) Only need to multiply fractions.
Rule: invert and multiply.
Example: (3/4)÷(5/7) = (3/4)x(7/5)
1) Second number is inverted using multiplicative inverse.
2) Multiplicative inverse of x is 1/x
We can simplify subtraction in the same way.
1) We don't need "special" subtraction rules.
2) Only need to add signed numbers.
Rule: invert and add.
Example: (-2)-(-2) = (-2) + (2) = 0
1) Second number is inverted using additive inverse.
2) Additive inverse of n is -n (simply change the sign)