Final answer:
The final temperature after a 20°F drop from 19°F is -1°F, represented by the addition expression 19°F + (-20°F).
Step-by-step explanation:
To represent the temperature change diagrammatically, we can use a simple number line or temperature scale. Initial temperature is at 19°F. When the temperature falls by 20°F, the number line will show a decrease from the initial point. To write an addition expression for the final temperature:
Initial Temperature = 19°F
Temperature Change = -20°F (since the temperature is falling)
Addition Expression: Final Temperature = Initial Temperature + Temperature Change
= 19°F + (-20°F)
= -1°F (This is the final temperature after the drop)