1. How to Use a Number Line Model
Integers and Rational Numbers

2. Starting Temperature + Change in Temperature = Ending Temperature
Number Line Equation
When finding the temperature change, write down the starting temperature and ending temperature in the number sentence below.
Starting Temperature + Change in Temperature = Ending Temperature

3. Finding Temperature Change
For example the temperature rose from -4°F to 45°F.
From -4°F to 0°F is a change of +4°F.
From 0°F to 45°F is a change of +45°F.
So the total change is +49°F.
The following number sentences show this.
-4 + n = +45
= +45

4. Finding Temperature Change
= +45
The sign of the change in temperature shows the direction of the change.
In this case, +49 means the temperature increased 49°F.

5. Finding Temperature Change
If the temperature had instead dropped 10°F from -4°F, you would write the change as -10°F.
= n
= -14