Key Concepts

Multiplicative Inverse

Definition:  The reciprocal of a non-zero number.  If you multiply a non-zero number by its multiplicative inverse you get 1.  Remember, the multiplicative inverse will have the same sign as the original number.

The Sign of a Quotient

• The quotient of two real numbers with the same sign is positive.
• The quotient of two real numbers with different signs is negative.
• The quotient of 0 and any nonzero real number is 0.

Finding the Mean

To find the mean of a set of numbers, find the sum of the numbers, then divide by how many numbers are in the set.

Example:  (7, -4, 1, -9, -6)

7 + (-4) + 1 + (-9) + (-5) = -10
-10/5 = -2  (There are five numbers in our set, so we divide by 5)
The mean is -2.

Simplifying Quotients

To simplify quotients with sums or differences in the numerator, you can divide up the numerator and take each term over the whole denominator.  For example:

Homework

p. 106 #4-40 even