Question
Sebastian was in a hotel lobby and took the elevator up 7 floors to his room.
Then he took the elevator down 9 floors to the parking garage. He described his movement with the expression below.
9 + (-7)
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(1 point)
• Sebastian should have used -9 and 7.
• Sebastian should have used 0 and -9.
• Sebastian should have started at zero before adding -7.
Then he took the elevator down 9 floors to the parking garage. He described his movement with the expression below.
9 + (-7)
NOTE: There is a check answer button in the bottom right corner. Click this to check your answer before moving on to the next question. It will not tell you the correct answer, but it will tell you if the answer you selected is correct. You can use this feature once per question.
(1 point)
• Sebastian should have used -9 and 7.
• Sebastian should have used 0 and -9.
• Sebastian should have started at zero before adding -7.
Answers
GPT-4o mini
To understand Sebastian's movements clearly:
1. He goes **up 7 floors** to his room, which can be represented as **+7**.
2. He then goes **down 9 floors** to the parking garage, which can be represented as **-9**.
Given his movements, the correct way to express them in a mathematical equation could be:
Starting position (0) + 7 (up) - 9 (down) = 0 + 7 - 9.
The expression he used, **9 + (-7)**, seems to imply that he started at a point higher than zero and then moved to a lower position, which doesn’t fully represent his journey from the ground floor up and then down.
Now, examining the options:
1. **Sebastian should have used -9 and 7.** - This does not accurately capture the movements since he moved up first then down.
2. **Sebastian should have used 0 and -9.** - This ignores the upward movement of 7 floors altogether.
3. **Sebastian should have started at zero before adding -7.** - This suggests he should account for starting at the ground level (0) and then moving up 7 floors before moving down 9. This is the most accurate representation of his actions.
Therefore, the best choice is:
- **Sebastian should have started at zero before adding -7.**
1. He goes **up 7 floors** to his room, which can be represented as **+7**.
2. He then goes **down 9 floors** to the parking garage, which can be represented as **-9**.
Given his movements, the correct way to express them in a mathematical equation could be:
Starting position (0) + 7 (up) - 9 (down) = 0 + 7 - 9.
The expression he used, **9 + (-7)**, seems to imply that he started at a point higher than zero and then moved to a lower position, which doesn’t fully represent his journey from the ground floor up and then down.
Now, examining the options:
1. **Sebastian should have used -9 and 7.** - This does not accurately capture the movements since he moved up first then down.
2. **Sebastian should have used 0 and -9.** - This ignores the upward movement of 7 floors altogether.
3. **Sebastian should have started at zero before adding -7.** - This suggests he should account for starting at the ground level (0) and then moving up 7 floors before moving down 9. This is the most accurate representation of his actions.
Therefore, the best choice is:
- **Sebastian should have started at zero before adding -7.**