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Positive/Negative Integer Rules

Positive and Negative Integer Rules, a selection of answers from the Dr. Math archives.

Negative Number Rules

When do two negative numbers equal a positive?

Manipulating Positive and Negative Numbers

Could you explain the rules for adding, subtracting, multiplying, and dividing positive and negative numbers?

Signs: Rules, Number Line

What is (-) - (+) = ? or (+) + (-) = ?

Subtracting Numbers by Walking a Number Line

For example: -8.1- -6.9 = -1.2 and -9.9- -11.1 = 1.2. All the numbers are negative, so why is the answer to the first problem negative but the second isn't?

And see:

Negative x Negative = Positive - Dr. Math FAQ

Why does a negative times a negative equal a positive? Does this ever happen in the real world?