Starting at -5°F on the number line and falling 9°F means moving left by 9 units. Using a skip count of 2's: -5, -7, -9, -11, -13, -15, -17, -19, -21, -23. Therefore, the temperature after falling 9°F is -23°F.
The initial temperature was -5°F, and it fell by 9°F. Representing this on a number line with a skip count of 2's, starting at -5 and moving left by 9 units, we get a sequence: -5, -7, -9, -11, -13, -15, -17, -19, -21, -23. Thus, the final temperature is -23°F.
The negative values indicate a decrease in temperature, and each unit represents a 2°F drop. Consequently, after falling 9°F, the temperature reached -23°F. This demonstrates the use of a number line to illustrate and calculate temperature changes, especially when counting by intervals other than 1.