Let's analyze each sum to check for an error of addition by one:
1. Example A: [tex]$35,427 + 63,562 = 98,889$[/tex]
- Perform the actual addition: [tex]\(35,427 + 63,562 = 98,989\)[/tex]
- Compare with the given result: [tex]\(98,889\)[/tex]
- Difference: [tex]\(98,889\)[/tex] is [tex]\(100\)[/tex] less than [tex]\(98,989\)[/tex]. This is not an error by one.
2. Example B: [tex]$17,642 + 72,345 = 89,987$[/tex]
- Perform the actual addition: [tex]\(17,642 + 72,345 = 89,987\)[/tex]
- Compare with the given result: [tex]\(89,987\)[/tex]
- Difference: The given result [tex]\(89,987\)[/tex] is exactly the correct sum. No error here.
3. Example C: [tex]$43,724 + 54,263 = 97,987$[/tex]
- Perform the actual addition: [tex]\(43,724 + 54,263 = 97,987\)[/tex]
- Compare with the given result: [tex]\(97,987\)[/tex]
- Difference: The given result [tex]\(97,987\)[/tex] is exactly the correct sum. No error here.
4. Example D: [tex]$28,546 + 61,352 = 89,898$[/tex]
- Perform the actual addition: [tex]\(28,546 + 61,352 = 89,898\)[/tex]
- Compare with the given result: [tex]\(89,898\)[/tex]
- Difference: The given result [tex]\(89,898\)[/tex] is exactly the correct sum. No error here.
Given the comparisons:
- Example A has a significant discrepancy and is not an error of one unit.
- Examples B, C, and D show no discrepancies at all.
Therefore, none of the examples provided is an error of addition by one.
