A negative number divided by a negative number always yields a positive number. For instance, -4 / -2 = 2. In other words, there are two -2s in -4. More »

Multiplying or dividing both sides of an equation by a negative number changes the inequality of the equation, because it changes the sign of each side of the equation. On both sides, what was positive becomes negative, ... More »

The multiplicative inverse of a negative number must also be a negative number. By definition, the product of a number and its multiplicative inverse is (positive) 1, which cannot be achieved by multiplying a positive an... More »

The fact that a negative times a negative equals a positive can be proven mathematically using algebraic manipulation. Specifically, it can be proven using the equation x = (a)(b) + (-a)(b) + (-a)(-b), where a and b are ... More »

According to Math Open Reference, pi is a mathematical constant obtained by dividing the circumference of any circle by its diameter. Pi is about 22/7 or 3.142. However, no one knows its exact value. More »

Adding two positive integers results in a positive number, and adding two negative integers yields a negative number. Multiplying two negative or two positive integers makes a positive number, but multiplying a negative ... More »

A negative minus a negative is equal to another negative number, a positive number or zero, depending upon the numbers in the equation. Subtracting a negative number from another negative number is the same thing as addi... More »