Sebastian was in a hotel lobby and took the elevator up 8 floors to his room. Then he took the elevator down 5 floors to the parking garage. He described his movement with the expression below.

Question

5+(−8)



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(1 point)
Responses

Sebastian should have used –5 and 8.
Sebastian should have used –5 and 8. - no response given

Sebastian should have started at zero before adding –8.
Sebastian should have started at zero before adding –8. - no response given

Sebastian should have used 0 and –8.
Sebastian should have used 0 and –8. - no response given

Sebastian should have switched the two addends and written −8+5
.
Sebastian should have switched the two addends and written negative 8 plus 5. - incorrect

Answer 1

To analyze Sebastian's movements more clearly, we can summarize what he did as follows:

1. Sebastian started from the ground floor (we can consider this as 0).
2. He took the elevator up 8 floors (which would be +8).
3. Then he took the elevator down 5 floors (which would be -5).

Combining these movements, we can express it mathematically as:

\[ 0 + 8 - 5 \] or simply, \[ 8 - 5 \]

The expression given (5 + (−8)) does not accurately represent Sebastian's movement as it does not start from an initial floor. Instead, the correct representation of his complete journey is more like starting at 0 (ground floor), moving up 8, and then moving down 5.

From the answer options you provided, the best choice would be:

Sebastian should have started at zero before adding –8.

This reflects that he should account for his starting point when considering his elevator movements.