The document provides examples and explanations for dividing real numbers, including finding multiplicative inverses, determining the sign of quotients based on the signs of the numbers, and calculating the mean of a data set. It demonstrates how to simplify expressions by dividing both the numerator and denominator by the same value. The examples guide the reader through dividing positive and negative numbers, as well as calculating the mean minimum daily temperature over a five day period.

1. 2.6 Divide Real
Numbers

2. Key concepts:
• Multiplicative inverse: the reciprocal
– 5 the reciprocal is 1
5
–2 the reciprocal is 5
5 2
• The sign of a Quotient
– same sign = positive
– different sign = negative

3. Example 1 Find multiplicative inverses of numbers
1
a. The multiplicative inverse of – is – 5 because
1 5
– • ( – 5) = 1 .
5
6 7
b. The multiplicative inverse of – is – because
6 7 7 6
– • – = 1.
7 6

4. Example 2 Divide real numbers
Find the quotient.
a. –16 ÷ 4
5
b. –20 ÷ –
3

5. Example 3 Find the mean
TEMPERATURES
Barrow, Alaska, is the northernmost settlement in the
United States. The daily minimum temperatures in
Barrow for February 1–5, 2004 are shown. Find the mean
daily minimum temperature.
Day in February 1 2 3 4 5
Minimum
temperature (°F) –21 –29 –39 –39 –22

6. Example 3 Find the mean
SOLUTION
To find the mean daily minimum temperature, find the
sum of the minimum temperatures for the 5 days and
then divide the sum by 5.
–21 + ( –29) + ( –39) + ( –39) + ( –22)
Mean =
5
–150
= = –30
5
ANSWER
The mean daily minimum temperature was –30°F.

7. Example 4 Simplify an expression
36x – 24
Simplify the expression .
6
36x – 24
=
6

8. Guided Practice for Example 4
– 10z – 20
4. Simplify the expression .
–5