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I don't really get what you are aiming at nor what your example has to do with what we said this morning. What we were talking about was the statement that - + - = + ("negative added to negative is positive"). This is just wrong. I think the guy who posted this mixed it up with: - * - = + ("negative multiplied with negative is positive").

An easy to understand example would be this: One day I take 5 apples from you so you got -5 apples. The next day I am taking another 10 apples from you. So your stock of apples would be: -5 apples and -10 apples is -15 apples.

try looking at it like this if you write -1 +1 -1 = -1

try taking away or canceling out the neg/positives on the left side. so + cancel out - and - is left. then you are only left with one - so your answer is negative.

2concrete examples found on the web:

tank levels rising/falling:
Example: The tank has 30,000 litres, and 1,000 litres are taken out every day. What was the level 3 days ago?
We know the tank has -1,000 every day, and we need to subtract that 3 times (to go back 3 days), so the change will be:
-3 × -1,000 = +3,000
The full calculation is:
30,000 + (-3 × -1,000) = 30,000 + 3,000 = 33,000
So 3 days ago there was 33,000 litres.

Debt

Debt is a good example of a negative number. One common form of debt is a mortgage in which you owe the bank money because the bank paid for your house. It is also common for an employer to deduct a mortgage payment from an employee's paycheck to help the employee keep on schedule with the payments.

Suppose $700 is being deducted each month to pay the mortgage. After six months, how much money has been taken out of the pay for the mortgage? We can figure out the answer by doing multiplication.

6 * -$700 = -$4,200

This is an illustration of a positive times a negative resulting in a negative.

Nowsuppose that, as a bonus, the employer decides to pay the mortgage for one year. The employer removes the mortgage deduction from the monthly paychecks. How much money is gained by the employee in our example? We can represent "removes" by a negative number and figure out the answer
by multiplying.

-12 * -$700 = $8,400

This is an illustration of a negative times a negative resulting in a positive.

And by math:
watch this calcul: A=(-4)x[(+2)+(-2)] -->A=0 (because -2+2=0)
But multiplication is also distributive over addition so A=(-4)x(+2)+(-4)x(-2) means A=(-8)+(-4)x(-2). We know A=0 so 0=(-8)+(-4)x(-2) consequently 8=(-4)x(-2)

and do not foget -(-x)= (-1)*(-x) we are just lazy to writte the 1 which has no consequence on the caclcul

omnomnomn