To evaluate whether Samantha's answer of 2.4 is reasonable for the expression -5.3 + 7.9, let's analyze the answers given.
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Actual Calculation: -5.3 + 7.9 = 2.6 (This demonstrates that Samantha's initial computation was incorrect).
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Rounded Values:
- Rounding -5.3 to the nearest whole number gives -5.
- Rounding 7.9 to the nearest whole number gives 8.
- When we sum these rounded values: -5 + 8 = 3.
Now, let's review the provided answer options:
A. Since -5.3 rounds to -5 and 7.9 rounds to 8, the sum rounds to 3. Her answer of 2.4 is not equal to 3. So, it is not reasonable. (This is correct because 3 is not close to 2.4).
B. Since -5.3 rounds to -5 and 7.9 rounds to 7, the sum rounds to 2. Her answer of 2.4 rounds to 2. So, it is reasonable. (This is incorrect because 7.9 rounds to 8, not 7).
C. Since -5.3 rounds to -6 and 7.9 rounds to 7, the sum rounds to 1. Her answer of 2.4 rounds to 2. So, it is reasonable. (This is incorrect; -5.3 does not round to -6).
D. Since -5.3 rounds to -6 and 7.9 rounds to 8, the sum rounds to 2. Her answer of 2.4 is not equal to 2. So, it is not reasonable. (This is incorrect because -5.3 does not round to -6).
Looking at the evaluations, the most accurate conclusion based on the rounding and the student's answer is:
A. Since -5.3 rounds to -5 and 7.9 rounds to 8, the sum rounds to 3. Her answer of 2.4 is not equal to 3. So, it is not reasonable.