A meteorologist used the expression below to describe how the temperature changed.
[tex]$-5+(-4)$[/tex]
Which statement could describe how the temperature changed?
A. The temperature was -5 degrees, then it increased 4 degrees.
B. The temperature was -5 degrees, then it decreased 4 degrees.
C. The temperature was 5 degrees, then it increased 4 degrees.
D. The temperature was 5 degrees, then it decreased 4 degrees.
Answer (2)
The expression − 5 + ( − 4 ) means starting at -5 and decreasing by 4.
Decreasing by 4 is the same as adding -4.
The correct statement is: The temperature was -5 degrees, then it decreased 4 degrees.
The final answer is: The temperature was -5 degrees, then it decreased 4 degrees.
Explanation
Understanding the Expression The expression − 5 + ( − 4 ) represents a temperature that starts at -5 degrees and then decreases by 4 degrees. Adding a negative number is the same as subtracting a positive number.
Analyzing the Statements Let's analyze the given statements:
The temperature was -5 degrees, then it increased 4 degrees. This would be represented by the expression − 5 + 4 .
The temperature was -5 degrees, then it decreased 4 degrees. This matches our expression − 5 + ( − 4 ) .
The temperature was 5 degrees, then it increased 4 degrees. This would be represented by the expression 5 + 4 .
The temperature was 5 degrees, then it decreased 4 degrees. This would be represented by the expression 5 − 4 .
Conclusion Therefore, the statement that accurately describes the temperature change is: "The temperature was -5 degrees, then it decreased 4 degrees."
Examples
Understanding temperature changes is crucial in many real-life scenarios. For example, if you are planning a hike, knowing the starting temperature and how much it will decrease during the day helps you prepare the right clothing. Similarly, in cooking, understanding temperature changes is essential for baking or grilling food properly. In finance, negative numbers can represent debt or losses, and understanding how these values change is important for managing your budget.
The expression − 5 + ( − 4 ) means starting at − 5 degrees and decreasing by 4 degrees. The correct statement that describes this change is: "The temperature was − 5 degrees, then it decreased 4 degrees." Therefore, option B is the correct choice.
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