Question

In Juneau, Alaska, the temperature was −15°F in the afternoon. As a cold front approached, the temperature dropped 9°F. Write a subtraction expression to determine the new temperature. Then determine and interpret the difference.

a) −15°F−9°F=−24°F
b) −15°F−(−9°F)=−6°F
c) −15°F+9°F=−6°F
d) −15°F×9°F=−135°F

Answer 1

The correct subtraction expression to determine the new temperature after a cold front in Juneau, Alaska is −15°F + 9°F, which equals −6°F. This shows the temperature became slightly less cold after dropping by 9°F from the initial −15°F.

Step-by-step explanation:

To determine the new temperature after a cold front in Juneau, Alaska, which has dropped the temperature, we use a subtraction expression. Starting at −15°F, if the temperature drops by 9°F, we calculate it as −15°F minus (minus 9°F), which is −15°F−(−9°F). This is equivalent to −15°F + 9°F because subtracting a negative number is like adding the positive value of that number.

So the correct subtraction expression and calculation would be:
−15°F + 9°F = −6°F.

Therefore, the new temperature would be −6°F after the temperature drops by 9°F. This result represents the environment becoming slightly less cold compared to the initial temperature of −15°F.