A Guide to the GRE/Positives and Negatives
Positives & Negatives
Subtracting a negative is the same as adding a positive.
5 + -3 = 5 – 3 = 2
Adding a negative is the same as subtracting a positive.
2 + -5 = 2 – 5 = -3
Multiplying a negative and a positive equals a negative.
5(-3) = -15
Multiplying a negative and a negative equals a positive.
-7(-3) = 7(3) = 21
Thus, multiplying any odd number of negatives together equals a negative, while multiplying any even number of negatives together equals a positive.
1. What is the value of 8(-4)?
2. If -2 - y is positive, then is y negative or positive?
3. x77 is positive. Is x negative or positive?
Answers to Practice Questions
Multiplying a positive by a negative equals a negative.
2. y must be negative (and must be less than -2)
Subtracting a negative is the same as adding a positive. For example, y could equal -3. -2 - -3 = -2 + 3 = 1.
3. x must be positive.
A negative multiplied by a negative equals a positive, while a negative multiplied by a negative equals a negative. Therefore, -1(-1)(-1) is negative, while -1(-1)(-1)(-1) is positive. Thus, any time an odd number of negatives are multiplied together, they equal a negative - meaning x must be positive, since 77 xs multiplied together are positive.